CN115805238A - A pipe-making method for reducing surface defects of pure nickel cold-rolled seamless pipe - Google Patents

Abstract

The invention discloses a pipe-making method for reducing the surface defects of pure nickel cold-rolled seamless pipes. A two-roll cold-rolling mill, a two-roll cold-rolling mill and a three-roll cold-rolling mill are successively used to roll a billet with a specification of Ф80×7.5 mm. A finished blank with a specification of Ф48.3×1.65mm is produced. The present invention effectively avoids the occurrence of wave-shaped defects by optimizing the feed rate and wall thickness reduction during cold rolling of the tube; through the enhanced inspection and grinding of the surface of the blank tube, the frequency of on-line inspection of the pass rolling groove is increased , effectively reducing pits (pit pits) in the rolling of waste tubes; by optimizing the deformation tools such as mandrels and chutes, and rationally adjusting the feed rate, the friction damage of the inner surface is effectively reduced.

Description

A pipe-making method for reducing surface defects of pure nickel cold-rolled seamless pipe

technical field

The present invention relates to the cold-processing pipe-making technology for producing seamless steel pipes in the metallurgical and mechanical industries, more specifically, relates to a pipe-making method for reducing surface defects of pure nickel cold-rolled seamless pipes, especially suitable for finished products with an outer diameter of 10 mm to 50 mm Nickel201 pure nickel seamless pipe is produced by cold rolled pipe.

Background technique

Seamless steel pipe is a common metallurgical steel product. Metal nickel has excellent high temperature corrosion resistance, high toughness, ductility and forgeability, good mechanical, physical and process properties, and special corrosion resistance and oxidation resistance. It has excellent resistance to strong alkali corrosion, so it is often used in various strong alkali-resistant equipment fields such as alkali manufacturing industry, chlor-alkali chemical industry and organic chloride production, food processing industry, high-temperature halogen and salt corrosion environment, electronic instrument parts, water treatment, etc. . At present, the nickel pipes made of metal nickel are all pure nickel seamless pipes, and no welded pipes have survived, and the pipe-making standards for pure nickel seamless pipes are: Chinese National Standard GB/T2882-2005 and American National Standard ASTM B163, ASTM B165. However, due to the scarcity of nickel metal resources on the earth, the production process of pure nickel seamless pipes is complicated, the technical difficulty is high, and the production cost is high, which limits the production and application of pure nickel seamless pipes.

Nickel201 pure nickel seamless pipe is a new type of seamless steel pipe developed and produced internationally in recent years. It can be used in caustic soda production equipment in the petrochemical industry. The finished product specifications are Φ13.7×1.2×5000mm, Φ32×4.5×4000mm, Φ48.3× 1.6×1400mm, American Standard ASTM B163 implemented. According to tube blank preparation (round steel peeling, end surface processing, centering hole, inspection) → blank tube preparation (tube blank heating, high temperature perforation, blank tube inspection) → blank tube pickling → blank tube finishing (cutting tube to length, surface grinding)→cold-rolled pipe→pickling→intermediate inspection→heading→lubrication→cold-drawn pipe→finishing (straightening)→pickling→cutting→finished product inspection and other technological processes for production. According to the specifications of the finished pipe, the process can choose cold-rolled pipe or cold-rolled + cold-drawn pipe-making two process methods, and the pure nickel seamless steel pipe after the pipe-making process can meet the technical requirements of users.

It can be seen from the above-mentioned process that the cold-rolled tube process is a key process that determines the production quality and efficiency of pure nickel seamless tubes. The seamless cold-rolled pipe process is to use a periodic cold-rolled pipe machine to carry out rolling deformation processing on the blank pipe under normal temperature conditions. According to the number of rolls, the periodic cold rolling mill is divided into two-roll periodic type and multi-roll periodic type. The most commonly used in multi-roll periodic type is three-roll periodic type. The characteristics of cold-rolled seamless steel tubes are: strong wall reduction ability, large pass surface reduction rate, good processing accuracy, high yield rate, low metal loss and high yield rate, but slow production speed, inconvenient specification change, tool mold The cost and processing cost are high, and the structure of the periodic cold rolling pipe mill is complex, the equipment investment cost is large, and the daily use and maintenance cost is high. It is mainly used for the production of seamless steel pipes such as stainless steel and alloy steel.

The two-roller periodic cold-rolled pipe mill consists of a rolling mechanism, a feed rotary mechanism, a transmission mechanism, a mandrel chuck mechanism, a bed support mechanism, a feeding and blanking mechanism, a hydraulic system, a process lubrication system, an electrical automation control system, Composed of pneumatic system and auxiliary mechanism. Among them, the function of the rolling mechanism is to carry out cold deformation processing on the blank tube of the seamless steel pipe under normal temperature working conditions through the deformation tool composed of the plug and the pass. The working principle of the rolling is: the depth of the semicircular rolling groove in the middle of the single pair of passes changes uniformly from deep to shallow on the entire pass circumference, and the passes are used in pairs according to the rolling specifications during rolling, that is, two The circular hole formed by the pass pattern changes from large to small, so as to realize the reduction of pipe diameter, thinning of pipe wall and extension of pipe. When the roll rotates once, the pass installed in the middle of the roll completes a change cycle synchronously, and the billet tube completes a feed (feed) amount and a synchronous rotation amount within a change cycle, and then reversely rolls under the drive of the roll. Rolling movement... In this way, the tube rolling (diameter reduction, wall reduction and extension) processing is completed repeatedly. When the seamless steel pipe is rolled, when the pass contacts the blank tube, the diameter of the contacted section is gradually reduced and the wall thickness is thinned at one time; when the roll rotates for one revolution, the blank tube of the section passes through the rolling groove of the pass to realize forging Rolling, finishing rolling, sizing and other functions are completed in one go. The rolling speed is fast, the rolling force is large, the deformation of each pass is large, the processing passes are few, and the production cycle is short, so it is suitable for the cold rolling production of seamless steel pipes with high deformation resistance and large wall and diameter reduction.

The three-roller periodic cold-rolled pipe mill is composed of a rolling mechanism, a feed rotary mechanism, a transmission mechanism, a mandrel chuck mechanism, a bed support mechanism, a feeding and blanking mechanism, a hydraulic system, a process lubrication system, an electrical automation control system, Composed of pneumatic system and auxiliary mechanism, the rolling mechanism is completely different from that of the two-roller periodic cold-rolled pipe mill. The rolls composed of three sets of equal-diameter rolling grooves in the middle of the trunnions at both ends replace the pass, and the deformation formed by the plug The tool performs cold deformation processing on the blank pipe of the seamless steel pipe under normal temperature conditions. Its rolling working principle is: three rolls are symmetrically arranged on the vertices of an equilateral triangle centered on the rolling center line, and the axis line of the rolls and the rolling center line are inclined at two different angles, one for feeding (feeding) ) angle, and the other is a rolling angle. The billet tube realizes diameter reduction, wall reduction and extension in a closed ring composed of three rolls and a plug. The deformation of the reduced diameter of the three-roller periodic cold-rolled pipe is smaller than that of the two-roller periodic cold-rolled pipe mill, and the deformation of the reduced wall is relatively large, so it can improve the surface quality of the inner wall of the seamless steel pipe, which belongs to the finishing rolling deformation process. The tube rolling has high precision and good surface quality, which is suitable for the finish rolling production of seamless steel tubes with high requirements on the surface quality of the inner wall, and is also commonly used in the cold rolling production of seamless steel tubes with thin wall thickness.

According to the finished specifications of Nickel201 pure nickel seamless pipe Φ13.7×1.2×5000mm, Φ32×4.5×4000mm, Φ48.3×1.6×1400mm, LG-80 two-roller periodic cold rolling mill and LG-55 two Roller periodic cold-rolled pipe mill or LG-60H two-roller periodic cold-rolled pipe mill, LD-60 three-roller periodic cold-rolled pipe mill and KPW-50VRM high-speed cold-rolled pipe mill form a continuous rolling production line for Nickel201 pure nickel-free Cold-rolled tube production for seamed tubes, namely:

Table 1: Nickel201 pure nickel seamless pipe cold rolling pipe process table

According to different product specifications, LG-80→LG-55→KPW-50 can be used to roll the blank specification Ф80×7.5mm into Ф38×5.0mm and Ф25×1.5mm semi-finished products, and LG-80→LG-60H→LD- 60 is rolled from a billet with a specification of Ф80×7.5mm to a finished product Ф48.3×1.65mm, and then processed as a finished product or a semi-finished product according to the specifications of the actual finished product. The above-mentioned cold-rolled tube process is relatively mature, and can meet the cold-rolled tube production of Nickel201 pure nickel seamless tube, but there are still certain problems, namely:

1) There are pits (pit pits) on the outer surface of the blank pipe when it is rolled: it appears when the blank pipe of the LG-80 two-roller periodic cold-rolled pipe mill is rolled, and the defect can be seen at a glance after pickling. Timely disposal will cause the defects to be deepened and aggravated during the subsequent rolling of the tube, forming intermittent or continuous cracks, and causing quality accidents. The main reason is that the surface defects of the barren pipe after the high-temperature perforation of the round steel are not completely eliminated or the defects are not thoroughly ground before entering the subsequent rolling process, and the pitting of the cold-rolled rolling grooves cannot be dealt with in time In addition, it is closely related to the feed rate of the rolled tube.

2) Scratches on the inner surface of pure nickel pipes: mainly appear in the rolling of LD-60 three-roller periodic cold-rolled pipe mills. The amount of deformation and feed are closely related. In addition, factors such as unclear inner wall of the billet tube material, bending of the tube material, bending of the mandrel rod, and small chamfer at the end of the mandrel rod will also cause rubbing damage to the inner wall of the pure nickel seamless pipe.

3) The wavy shape of the pure nickel pipe: the so-called wavy shape is that the outer circumference is distributed along the length direction with ring-shaped unevenness, like continuous or intermittent deformation of waves, which mainly occurs in the KPW-50VRM high-speed cold-rolled pipe mill. The main reason is that the large amount of feeding (feeding) during rolling is closely related to the large amount of wall thickness reduction. In addition, the feeding (feeding) of the billet tube is unstable, the back slope of the support plate is not enough, and the pass sizing section It is caused by the failure of the cone shape after wear, and the poor processing of the opening part of the rolling groove and the mismatch of the synchronization of the feed and rotary motion output by the equipment.

In summary, due to the metal properties of nickel itself and related factors in the cold rolling of pure nickel seamless pipes, the finished product specifications for caustic soda plants are Φ13.7×1.2×5000mm, Φ32×4.5×4000mm, Φ48. 3×1.6×1400mm Nickel201 pure nickel seamless pipe has surface defect damage in the cold-rolled pipe, which affects the production quality and efficiency of the product to a certain extent, and has a negative impact on the production of the enterprise. According to the technical requirements of Nickel201 pure nickel seamless pipe, relying on the company's long-term accumulated technical reserves and advanced equipment and other advantages, carry out targeted technical improvements on the existing cold-rolled pipe production process, and further improve the cold-rolled pure nickel seamless pipe Excellent surface quality, reduce surface defects, meet production technical requirements, and promote the core market competitiveness of enterprises.

Contents of the invention

In view of the above-mentioned defects existing in the prior art, the object of the present invention is to provide a pipe-making method for reducing surface defects of pure nickel cold-rolled seamless pipes, by optimizing the feed rate and wall thickness reduction during cold-rolled pipes , which effectively avoids the generation of wavy defects; through the enhanced inspection and grinding of the surface of the blank tube, the frequency of on-line inspection of the pass rolling groove is increased, and the pitting (pitting) in the rolling of the blank tube is effectively reduced; through optimization For deformation tools such as mandrel and chute, the feed rate can be adjusted reasonably to effectively reduce the friction damage of the inner surface.

To achieve the above object, the present invention adopts the following technical solutions:

The first aspect of the present invention provides a pipe-making method for reducing surface defects of pure nickel cold-rolled seamless pipes:

A two-roll cold rolling mill, a two-roll cold rolling mill, and a three-roll cold rolling mill are used in turn to roll the billet with a specification of Ф80×7.5 mm into a finished product supply billet with a specification of Ф48.3×1.65 mm.

Preferably, the pipe making method further includes the following passes:

Pass 0: Rolling with a two-roller cold rolling mill, rolling a billet with a specification of Ф80×7.5mm into a billet with a specification of Ф57×4.5mm;

Pass 1: Rolling with a two-roller cold rolling mill, rolling the billet with a specification of Ф57×4.5mm into a billet with a specification of Ф53×3.0mm;

Pass 2: Rolling with a three-roll cold rolling mill, rolling the billet with a specification of Ф53×3.0mm into a finished product supply billet with a specification of Ф48.3×1.65mm.

Preferably, in the pass 0, the rolling speed of the two-roll cold rolling mill is 60-70 times/minute, the pass gap is 0.3-1.0 mm, the rolling gap is 1.5-3.8 mm, and the feed rate is 3-6mm, the rotation angle is 41.5-42.2 degrees, the lubrication method adopts online large-flow thin oil lubrication, the billet re-inspection is added before rolling, and the pass type is re-inspected after rolling the three pipes;

In said pass 1, the rolling speed of the two-roll cold rolling mill is 68-80 times/min, the pass gap is 0.2-1.0 mm, the rolling gap is 1.5-3.2 mm, and the feed rate is 3-6 mm. The rotation angle is 41.5-42.2 degrees, and the lubrication method adopts online large-flow thin oil lubrication;

In the pass 2, the rolling speed of the three-roll cold rolling mill is 55-65 times per minute, the rolling gap is 0.5-2.0 mm, the feed rate is 3.5-4.5 mm, the rotation angle is 47.5-48.5 degrees, and the lubrication The method adopts online large-flow thin oil lubrication, and the deformation surfaces of chute, mandrel and roll adopt chamfering for smooth transition.

The second aspect of the present invention provides a method for reducing the surface defects of pure nickel cold-rolled seamless pipes:

Using a two-roll cold rolling mill and a two-roll cold rolling mill in turn, the billet with a specification of Ф80×7.5mm is rolled into a semi-finished product with a specification of Ф38×5.0mm, and then rolled into a finished product with a specification of Φ32×4.5mm.

Preferably, the pipe making method further includes the following passes:

Pass 0: Rolling with a two-roll cold rolling mill, rolling the billet with a specification of Ф80×7.5mm into a semi-finished product with a specification of Ф57×5.5mm;

Pass 1: Rolling with a two-roll cold rolling mill, rolling the semi-finished product with a specification of Ф57×5.5mm into a finished product with a specification of Ф38×5.0mm.

Preferably, in the pass 0, the rolling speed of the two-roll cold rolling mill is 60-70 times/minute, the pass gap is 0.3-1.0 mm, the rolling gap is 1.5-3.8 mm, and the feed rate is 3.5-6mm, the rotation angle is 41.5-42.2 degrees, the lubrication method adopts online large-flow thin oil lubrication, the billet re-inspection is added before rolling, and the pass type is re-inspected after rolling three pipes;

In said pass 1, the rolling speed of the two-roll cold rolling mill is 68-80 times/min, the pass gap is 0.2-1.0 mm, the rolling gap is 1.5-3.2 mm, and the feed rate is 4-6 mm. The rotation angle is 41.5-42.2 degrees, and the lubrication method adopts online large-flow thin oil lubrication.

The third aspect of the present invention provides a pipe-making method for reducing surface defects of pure nickel cold-rolled seamless pipes:

Using a two-roll cold rolling mill, a two-roll cold rolling mill, and a two-roll high-speed rolling mill in turn, the billet with a specification of Ф80×7.5mm is rolled into a semi-finished product with a specification of Ф25×1.5mm, and then rolled to Φ13.7×1.2mm The finished product for blank.

Preferably, the pipe making method further includes the following passes:

Pass 0: Rolling with a two-roll cold rolling mill, rolling the billet with a specification of Ф80×7.5mm into a semi-finished product with a specification of Ф57×4.5mm;

Pass 1: Rolling with a two-roll cold rolling mill, rolling the semi-finished product with a specification of Ф57×4.5mm into a semi-finished product with a specification of Ф38×3.0mm;

Pass 2: Roll the semi-finished product with a specification of Ф38×3.0mm into a finished product with a specification of Ф13.7×1.2mm by using a two-roll high-speed rolling mill.

Preferably, in the pass 0, the rolling speed of the two-roll cold rolling mill is 60-70 times/minute, the pass gap is 0.3-1.0 mm, the rolling gap is 1.5-3.8 mm, and the feed rate is 3-6mm, the rotation angle is 41.5-42.2 degrees, the lubrication method adopts online large-flow thin oil lubrication, the billet re-inspection is added before rolling, and the pass type is re-inspected after rolling the three pipes;

In said pass 1, the rolling speed of the two-roll cold rolling mill is 68-80 times/min, the pass gap is 0.2-1.0 mm, the rolling gap is 1.5-3.2 mm, and the feed rate is 3-6 mm. The rotation angle is 41.5-42.2 degrees, and the lubrication method adopts online large-flow thin oil lubrication;

In the pass 2, the rolling speed of the two-roll high-speed rolling mill is 110-140 times/min, the pass gap is 0.15-0.5 mm, the rolling gap is 1.2-2.8 mm, the feed rate is 3.5-5 mm, and the corner The inlet end is 31.0°C and the outlet end is 26.0°C. The lubrication method adopts the combination of online large-flow thin oil external lubrication and special rolling lubricant mandrel tail high-pressure input internal lubrication.

A pipe-making method for reducing surface defects of pure nickel cold-rolled seamless pipes provided by the present invention has the following beneficial effects:

1) The process design is reasonable, the process organization is smooth, safe, reliable, practical and efficient, which meets the technical requirements of Nickel201 pure nickel seamless pipe cold-rolled pipe and promotes the core competitiveness of the enterprise;

2) According to the steel characteristics and technical requirements of three finished specifications of Nickel201 pure nickel seamless pipes, organize and implement the cold rolling pipe process, which reduces the loss of surface defects of pure nickel pipes, improves the rolling quality of the surface continuously and stably, and saves energy Remarkable effect on emission reduction and consumption reduction;

3) Using LG-80 two-roll cold rolling mill→LG-60H two-roll cold rolling mill→LD-60 three-roll cold rolling mill, the billet specification Ф80×7.5mm is rolled into a finished product of Ф48.3×1.65mm, fully The characteristics of two-roll and three-roll cold rolling mills are utilized to ensure the quality and efficiency of finished product rolling;

4) Using LG-80 two-roll cold rolling mill→LG-55 two-roll cold rolling mill to roll the billet specification Ф80×7.5mm into Ф38×5.0mm semi-finished product, and supply billet for Φ32×4.5mm finished product, short process reduces rolling Pipe production cost, control wall thickness accuracy to create conditions for subsequent cold drawing processing;

5) Using LG-80 two-roll cold rolling mill→LG-55 two-roll cold rolling mill→KPW-50 two-roll high-speed rolling mill, the billet specification Ф80×7.5mm is rolled into Ф25×1.5mm semi-finished product is Φ13.7×1.2 The billet supply of mm finished products makes full use of the characteristics of fast speed and high production capacity of the high-speed rolling mill, which is convenient for on-site production organization;

6) Through the enhanced inspection and grinding of the surface of the blank pipe, the frequency of on-line inspection of the pass rolling groove is increased, which effectively reduces the pitting (pit) curve in the rolling of the blank pipe;

7) By optimizing the feed rate and wall thickness reduction when cold-rolling tubes, the rolling gap and pass gap are guaranteed, and the generation of wavy defects is effectively avoided;

8) By optimizing the deformation tools such as mandrel and chute, the feed rate can be reasonably adjusted to effectively reduce the incidence of friction damage on the inner surface;

9) Strong versatility. It has certain reference, promotion and application value for the research and development of pure nickel seamless pipe cold-rolled pipe in the industry and industrial scale production. It can promote the localization of key materials in the field of domestic key engineering equipment and has broad market application prospects. The economic benefits are considerable.

Description of drawings

Fig. 1 is the cold rolling process flow chart of the Nickel201 pure nickel seamless pipe of finished product specification Ф48.3 * 1.65mm in the pipe making method of the present invention;

Fig. 2 is the cold rolling process flow chart of the Nickel201 pure nickel seamless pipe of finished product specification Φ 32 * 4.5mm in the pipe making method of the present invention;

Fig. 3 is the cold-rolling process flow chart of the Nickel201 pure nickel seamless pipe with finished product specification Φ13.7×1.2mm in the pipe-making method of the present invention.

Detailed ways

In order to better understand the above-mentioned technical solution of the present invention, the technical solution of the present invention will be further described below in conjunction with the drawings and embodiments.

In conjunction with shown in Fig. 1, a kind of pipe making method that reduces the surface defect of pure nickel cold-rolled seamless pipe provided by the first aspect of the present invention is the technical optimization of Nickel201 pure nickel seamless pipe cold-rolled pipe process:

Using LG-80 two-roll cold rolling mill, LG-60H two-roll cold rolling mill, and LD-60 three-roll cold rolling mill in turn to roll the billet with a specification of Ф80×7.5mm into a finished product with a specification of Ф48.3×1.65mm For blank. The cold-rolled tube process is shown in Table 1 below.

Table 1: Cold rolling process table of Nickel201 pure nickel seamless pipe with finished product specification Ф48.3×1.65mm

As shown in Table 1 above, the cold rolling process of Nickel201 pure nickel seamless pipe with finished product specification Ф48.3×1.65mm:

Pass 0: LG-80 two-roll cold rolling mill is used for rolling, and the billet with a specification of Ф80×7.5 mm is rolled into a billet with a specification of Ф57×4.5 mm. The technical points of this process include: the rolling speed of the LG-80 two-roll cold rolling mill is 60-70 times per minute, the pass gap is 0.3-1.0 mm, the rolling gap is 1.5-3.8 mm, and the feed rate is 3-3. 6mm, the rotation angle is 41.5-42.2 degrees, the lubrication method adopts online large-flow thin oil lubrication, the billet re-inspection is added before rolling, and the pass type is re-inspected after rolling the three pipes;

Pass 1: The LG-60H two-roll cold rolling mill is used for rolling, and the billet with a specification of Ф57×4.5mm is rolled into a billet with a specification of Ф53×3.0mm. The technical points of this process include: the rolling speed of the LG-60H two-roll cold rolling mill is 68-80 times per minute, the pass gap is 0.2-1.0 mm, the rolling gap is 1.5-3.2 mm, and the feed rate is 3-3. 6mm, the rotation angle is 41.5-42.2 degrees, and the lubrication method adopts online large-flow thin oil lubrication;

Pass 2: LD-60 is rolled with a three-roll cold rolling mill, and the billet with a specification of Ф53×3.0mm is rolled into a finished billet with a specification of Ф48.3×1.65mm. The technical points of this process include: the rolling speed of LD-60 three-roll cold rolling mill is 55-65 times per minute, the rolling gap is 0.5-2.0 mm, the feed rate is 3.5-4.5 mm, and the rotation angle is 47.5-48.5 degrees , The lubrication method adopts online large-flow thin oil lubrication, and the deformation surfaces of chute, mandrel and roll adopt chamfering for smooth transition.

In conjunction with shown in Fig. 2, a kind of pipe making method that reduces the surface defect of pure nickel cold-rolled seamless pipe provided by the second aspect of the present invention is the technical optimization of Nickel201 pure nickel seamless pipe cold-rolled pipe process:

Using LG-80 two-roll cold rolling mill and LG-55 two-roll cold rolling mill in turn, the billet with a specification of Ф80×7.5mm is rolled into a semi-finished product with a specification of Ф38×5.0mm, and then rolled into a Φ32×4.5mm Finished products for blanks. The cold-rolled tube process is shown in Table 2 below.

Table 2: Nickel201 pure nickel seamless pipe cold rolling process table with finished product specification Ф32×4.5mm

As shown in Table 2 above, the cold rolling process of Nickel201 pure nickel seamless pipe with finished product specification Ф32×4.5mm:

Pass 0: LG-80 two-roll cold rolling mill is used for rolling, and the billet with a specification of Ф80×7.5mm is rolled into a semi-finished product with a specification of Ф57×5.5mm. The technical points of this process include: the rolling speed of the LG-80 two-roll cold rolling mill is 60-70 times per minute, the pass gap is 0.3-1.0 mm, the rolling gap is 1.5-3.8 mm, and the feed rate is 3.5-3.5 mm. 6mm, the rotation angle is 41.5-42.2 degrees, the lubrication method adopts online large-flow thin oil lubrication, the billet re-inspection is added before rolling, and the pass type is re-inspected after rolling the three pipes;

Pass 1: The LG-55 two-roll cold rolling mill is used for rolling, and the semi-finished product with a specification of Ф57×5.5mm is rolled into a finished product with a specification of Ф38×5.0mm. The technical points of this process include: the rolling speed of the LG-55 two-roll cold rolling mill is 68-80 times per minute, the pass gap is 0.2-1.0mm, the rolling gap is 1.5-3.2mm, and the feed rate is 4- 6mm, the rotation angle is 41.5-42.2 degrees, and the lubrication method adopts online large-flow thin oil lubrication.

Shown in conjunction with Fig. 3, a kind of pipe making method that reduces the surface defect of pure nickel cold-rolled seamless pipe provided by the third aspect of the present invention is the technical optimization of Nickel201 pure nickel seamless pipe cold-rolled pipe process:

Using LG-80 two-roll cold rolling mill, LG-55 two-roll cold rolling mill, and KPW-50 two-roll high-speed rolling mill in turn, the billet with a specification of Ф80×7.5mm is rolled into a semi-finished product with a specification of Ф25×1.5mm, and then Rolling is the finished product of Φ13.7×1.2mm. The cold-rolled tube process is shown in Table 3 below.

Table 3: Cold rolling process table of Nickel201 pure nickel seamless pipe with finished product specification Ф13.7×1.2mm

As shown in Table 3 above, the cold rolling process of Nickel201 pure nickel seamless pipe with finished product specification Ф13.7×1.2mm:

Pass 0: LG-80 two-roll cold rolling mill is used for rolling, and the billet with a specification of Ф80×7.5mm is rolled into a semi-finished product with a specification of Ф57×4.5mm. The technical points of this process include: the rolling speed of the LG-80 two-roll cold rolling mill is 60-70 times per minute, the pass gap is 0.3-1.0 mm, the rolling gap is 1.5-3.8 mm, and the feed rate is 3-3. 6mm, the rotation angle is 41.5-42.2 degrees, the lubrication method adopts online large-flow thin oil lubrication, the billet re-inspection is added before rolling, and the pass type is re-inspected after rolling the three pipes;

Pass 1: The LG-55 two-roll cold rolling mill is used for rolling, and the semi-finished product with a specification of Ф57×4.5mm is rolled into a semi-finished product with a specification of Ф38×3.0mm. The technical points of this process include: the rolling speed of the LG-55 two-roll cold rolling mill is 68-80 times per minute, the pass gap is 0.2-1.0 mm, the rolling gap is 1.5-3.2 mm, and the feed rate is 3-3. 6mm, the rotation angle is 41.5-42.2 degrees, and the lubrication method adopts online large-flow thin oil lubrication;

Pass 2: Use KPW-50 two-roll high-speed rolling mill to roll the semi-finished product with a specification of Ф38×3.0mm into a finished product with a specification of Ф13.7×1.2mm. The technical points of this process include: the rolling speed of KPW-50 two-roll high-speed rolling mill is 110-140 times/min, the pass gap is 0.15-0.5mm, the rolling gap is 1.2-2.8mm, and the feed rate is 3.5-5mm , The inlet end of the corner is 31.0 degrees, and the outlet end is 26.0 degrees. The lubrication method adopts the combination of online large-flow thin oil external lubrication and special rolling lubricant mandrel tail high-pressure input internal lubrication.

To sum up, according to the steel characteristics and technical requirements of the three finished specifications of Nickel201 pure nickel seamless pipes, the production process of cold-rolled pipes under normal temperature conditions can be completed according to the production process, and the pure nickel pipes can be reduced. Surface defects, improving internal and external surface quality. The cold-rolled tubes after rolling either directly enter the subsequent finished product processing process, or are cold-drawn tube-making processes according to the requirements of the finished tube.

It should be pointed out that the technical solution provided by the present invention only involves the rolling process in cold-rolled pipes, and does not include heat treatment, finishing (cutting pipes to length, flattening, straightening), pickling (cleaning) and inspection , Preparation and installation of deformation tools (pass, roll, inner and outer molds, mandrel, plug) and other processes. At the same time, the size of the pass product is the nominal nominal size.

A pipe-making method for reducing surface defects of pure nickel cold-rolled seamless pipes is a technical optimization of the cold-rolled pipe process for Nickel201 pure nickel seamless pipes. According to three different finished product specifications, matching cold-rolled pipes are implemented The process makes full use of the existing equipment, gives full play to the characteristics of two-roll and three-roll cold rolling mills, highlights the advantages of short process and high production capacity, guarantees the quality and efficiency of finished rolling, facilitates on-site production organization, and reduces production costs. By optimizing the feed rate and wall thickness reduction during cold rolling, the generation of wave-shaped defects is effectively avoided; through the enhanced inspection and grinding of the surface of the blank tube, the frequency of on-line inspection of the pass rolling groove is increased, effectively Reduce pits (pit pits) in raw tube rolling; through optimizing mandrel, chute and other deformation tools, rationally adjust the feed rate, effectively reduce the friction damage of the inner surface. The process design is reasonable, the process organization is smooth, safe, reliable, practical and efficient, which meets the technical requirements of Nickel201 pure nickel seamless pipe cold-rolled pipe, reduces the loss of surface defects of pure nickel pipe, and improves the surface rolling quality. The core competitiveness of the enterprise is strengthened, and the effect of energy saving, emission reduction and consumption reduction is remarkable. Strong versatility, it has certain reference, promotion and application value for the research and development of pure nickel seamless pipe cold-rolled pipe in the industry and industrial scale production, and promotes the localization of key materials in the field of domestic key engineering equipment, with broad market application prospects and economic benefits considerable.

Example 1

Referring to Fig. 1 again, a steel pipe factory of a steel company uses the technical solution provided by the present invention on the cold processing production line of seamless steel pipes, and it is used for the caustic soda device of a technical renovation project of a key domestic petrochemical enterprise, and the finished product specification is Ф48. 3×1.65mm Nickel201 pure nickel seamless pipe cold-rolled pipe production. The cold-rolling equipment involved includes LG-80 two-roller periodic cold rolling mill, LG-60H two-roller periodic cold-rolling mill, LD-60 three-roller periodic cold-rolling mill, and the cold-rolled tube process is shown in the table below 1.

Table 1: Cold rolling process table of Nickel201 pure nickel seamless pipe with finished product specification Ф48.3×1.65mm

Pass 0: LG-80 two-roll cold rolling mill is used for rolling, and the billet with a specification of Ф80×7.5 mm is rolled into a billet with a specification of Ф57×4.5 mm. The technical points of this process include: the rolling speed of the LG-80 two-roll cold rolling mill is 65 times/min, the pass gap is 0.65 mm, the rolling gap is 2.65 mm, the feed rate is 4.5 mm, and the rotation angle is 41.85 degrees. The lubrication method adopts online high-flow thin oil lubrication, and the billet re-inspection is added before rolling, and the pass type is re-inspected after rolling the three pipes;

Pass 1: The LG-60H two-roll cold rolling mill is used for rolling, and the billet with a specification of Ф57×4.5mm is rolled into a billet with a specification of Ф53×3.0mm. The technical points of this process include: the rolling speed of LG-60H two-roll cold rolling mill is 74 times/min, the pass gap is 0.6mm, the rolling gap is 2.35mm, the feed rate is 4.5mm, and the rotation angle is 41.85 degrees. The lubrication method adopts online large flow thin oil lubrication;

Pass 2: LD-60 is rolled with a three-roll cold rolling mill, and the billet with a specification of Ф53×3.0mm is rolled into a finished billet with a specification of Ф48.3×1.65mm. The technical points of this process include: the rolling speed of LD-60 three-roll cold rolling mill is 60 times per minute, the rolling gap is 1.25mm, the feed rate is 4mm, the rotation angle is 48 degrees, and the lubrication method adopts online large-flow thin oil Lubrication, the deformation surfaces of chute, mandrel and roll adopt chamfering for smooth transition.

The cold-rolled pipe is the finished pipe, and after subsequent finishing, pickling, and inspection, the finished product is put into storage for delivery.

Example 2

Referring to Fig. 2 again, a steel pipe factory of a steel company uses the technical solution provided by the present invention on the cold processing production line of seamless steel pipes, and it is used for the caustic soda device of a technical renovation project of a key domestic petrochemical enterprise, and the finished product specification is Ф32× 4.5mm Nickel201 pure nickel seamless pipe cold rolled pipe production. The cold-rolling equipment involved includes LG-80 two-roller periodic cold rolling mill and LG-55 two-roller periodic cold-rolling mill. The cold-rolled tube process is shown in Table 2 below.

Table 2: Nickel201 pure nickel seamless pipe cold rolling process table with finished product specification Ф32×4.5mm

As shown in Table 2 above, the cold rolling process of Nickel201 pure nickel seamless pipe with finished product specification Ф32×4.5mm:

Pass 0: LG-80 two-roll cold rolling mill is used for rolling, and the billet with a specification of Ф80×7.5mm is rolled into a semi-finished product with a specification of Ф57×5.5mm. The technical points of this process include: the rolling speed of LG-80 two-roll cold rolling mill is 65 times/min, the pass gap is 0.65mm, the rolling gap is 2.65mm, the feed rate is 4.75mm, and the rotation angle is 41.85 degrees. The lubrication method adopts online high-flow thin oil lubrication, and the billet re-inspection is added before rolling, and the pass type is re-inspected after rolling the three pipes;

Pass 1: The LG-55 two-roll cold rolling mill is used for rolling, and the semi-finished product with a specification of Ф57×5.5mm is rolled into a finished product with a specification of Ф38×5.0mm. The technical points of this process include: the rolling speed of the LG-55 two-roll cold rolling mill is 74 times per minute, the pass gap is 0.6 mm, the rolling gap is 2.35 mm, the feed rate is 5 mm, the rotation angle is 41.85 degrees, the lubrication The method adopts online large flow thin oil lubrication.

The cold-rolled pipe is the intermediate product pipe, and after inspection, it will be used as a blank for the cold-drawn pipe for subsequent processing.

Example 3

A steel pipe factory of a steel company uses the technical solution provided by the present invention on the cold processing production line of seamless steel pipes. It is used in the caustic soda plant of a technical renovation project of a key domestic petrochemical enterprise, and the finished product specification is Ф13.7×1.2mm. Nickel201 pure nickel seamless pipe cold rolled pipe production. The cold rolling equipment involved includes LG-80 two-roll periodic cold rolling mill, LG-55 two-roll periodic cold rolling mill, and KPW-50 two-roll high-speed rolling mill. The cold-rolled tube process is shown in Table 3 below.

Table 3: Cold rolling process table of Nickel201 pure nickel seamless pipe with finished product specification Ф13.7×1.2mm

Pass 0: LG-80 two-roll cold rolling mill is used for rolling, and the billet with a specification of Ф80×7.5mm is rolled into a semi-finished product with a specification of Ф57×4.5mm. The technical points of this process include: the rolling speed of the LG-80 two-roll cold rolling mill is 65 times/min, the pass gap is 0.65 mm, the rolling gap is 2.65 mm, the feed rate is 4.5 mm, and the rotation angle is 41.85 degrees. The lubrication method adopts online high-flow thin oil lubrication, and the billet re-inspection is added before rolling, and the pass type is re-inspected after rolling the three pipes;

Pass 1: The LG-55 two-roll cold rolling mill is used for rolling, and the semi-finished product with a specification of Ф57×4.5mm is rolled into a semi-finished product with a specification of Ф38×3.0mm. The technical points of this process include: the rolling speed of the LG-55 two-roll cold rolling mill is 74 times per minute, the pass gap is 0.6 mm, the rolling gap is 2.35 mm, the feed rate is 4.5 mm, and the rotation angle is 41.85 degrees. The lubrication method adopts online large flow thin oil lubrication;

Pass 2: Use KPW-50 two-roll high-speed rolling mill to roll the semi-finished product with a specification of Ф38×3.0mm into a finished product with a specification of Ф13.7×1.2mm. The technical points of this process include: the rolling speed of the KPW-50 two-roller high-speed rolling mill is 125 times per minute, the pass gap is 0.325 mm, the rolling gap is 2 mm, the feed rate is 4.25 mm, and the corner inlet end is 31.0 degrees, The outlet end is 26.0 degrees, and the lubrication method adopts the combination of online large-flow thin oil external lubrication and special rolling lubricant mandrel tail high-pressure input internal lubrication.

The cold-rolled pipe is the intermediate product pipe, and after inspection, it will be used as a blank for the cold-drawn pipe for subsequent processing.

Those of ordinary skill in the art should recognize that the above embodiments are only used to illustrate the present invention, rather than as a limitation to the present invention, as long as within the scope of the spirit of the present invention, the above-described embodiments Changes and modifications will fall within the scope of the claims of the present invention.

Claims (9)

1. A pipe-making method for reducing surface defects of pure nickel cold-rolled seamless pipes, characterized in that: A two-roll cold rolling mill, a two-roll cold rolling mill, and a three-roll cold rolling mill are used in turn to roll the billet with a specification of Ф80×7.5 mm into a finished product supply billet with a specification of Ф48.3×1.65 mm. 2. The pipe-making method for reducing surface defects of pure nickel cold-rolled seamless pipes according to claim 1, wherein the pipe-making method further comprises the following passes: Pass 0: Rolling with a two-roller cold rolling mill, rolling a billet with a specification of Ф80×7.5mm into a billet with a specification of Ф57×4.5mm; Pass 1: Rolling with a two-roller cold rolling mill, rolling the billet with a specification of Ф57×4.5mm into a billet with a specification of Ф53×3.0mm; Pass 2: Rolling with a three-roll cold rolling mill, rolling the billet with a specification of Ф53×3.0mm into a finished product supply billet with a specification of Ф48.3×1.65mm. 3. The pipe-making method for reducing surface defects of pure nickel cold-rolled seamless pipes according to claim 2, characterized in that: in the pass 0, the rolling speed of the two-roll cold rolling mill is 60-70 times/ minutes, the pass gap is 0.3-1.0mm, the rolling gap is 1.5-3.8mm, the feed rate is 3-6mm, the corner is 41.5-42.2 degrees, the lubrication method is online large-flow thin oil lubrication, and the billet is added before rolling Re-inspection, re-inspection of pass type after rolling three pipes; In said pass 1, the rolling speed of the two-roll cold rolling mill is 68-80 times/min, the pass gap is 0.2-1.0 mm, the rolling gap is 1.5-3.2 mm, and the feed rate is 3-6 mm. The rotation angle is 41.5-42.2 degrees, and the lubrication method adopts online large-flow thin oil lubrication; In the pass 2, the rolling speed of the three-roll cold rolling mill is 55-65 times per minute, the rolling gap is 0.5-2.0 mm, the feed rate is 3.5-4.5 mm, the rotation angle is 47.5-48.5 degrees, and the lubrication The method adopts online large-flow thin oil lubrication, and the deformation surfaces of chute, mandrel and roll adopt chamfering for smooth transition. 4. A pipe-making method for reducing surface defects of pure nickel cold-rolled seamless pipes, characterized in that: Using a two-roll cold rolling mill and a two-roll cold rolling mill in turn, the billet with a specification of Ф80×7.5mm is rolled into a semi-finished product with a specification of Ф38×5.0mm, and then rolled into a finished product with a specification of Φ32×4.5mm. 5. The pipe-making method for reducing surface defects of pure nickel cold-rolled seamless pipes according to claim 4, characterized in that, the pipe-making method further comprises the following passes: Pass 0: Rolling with a two-roll cold rolling mill, rolling the billet with a specification of Ф80×7.5mm into a semi-finished product with a specification of Ф57×5.5mm; Pass 1: Rolling with a two-roll cold rolling mill, rolling the semi-finished product with a specification of Ф57×5.5mm into a finished product with a specification of Ф38×5.0mm. 6. The pipe-making method for reducing surface defects of pure nickel cold-rolled seamless pipes according to claim 5, characterized in that: in the pass 0, the rolling speed of the two-roll cold rolling mill is 60-70 times/ minutes, the pass gap is 0.3-1.0mm, the rolling gap is 1.5-3.8mm, the feed rate is 3.5-6mm, the corner is 41.5-42.2 degrees, the lubrication method is online large-flow thin oil lubrication, and the billet is added before rolling Re-inspection, re-inspection of pass type after rolling three pipes; In said pass 1, the rolling speed of the two-roll cold rolling mill is 68-80 times/min, the pass gap is 0.2-1.0 mm, the rolling gap is 1.5-3.2 mm, and the feed rate is 4-6 mm. The rotation angle is 41.5-42.2 degrees, and the lubrication method adopts online large-flow thin oil lubrication. 7. A pipe-making method for reducing surface defects of pure nickel cold-rolled seamless pipes, characterized in that: Using a two-roll cold rolling mill, a two-roll cold rolling mill, and a two-roll high-speed rolling mill in turn, the billet with a specification of Ф80×7.5mm is rolled into a semi-finished product with a specification of Ф25×1.5mm, and then rolled to Φ13.7×1.2mm The finished product for blank. 8. The pipe-making method for reducing surface defects of pure nickel cold-rolled seamless pipes according to claim 7, wherein the pipe-making method further comprises the following passes: Pass 0: Rolling with a two-roll cold rolling mill, rolling the billet with a specification of Ф80×7.5mm into a semi-finished product with a specification of Ф57×4.5mm; Pass 1: Rolling with a two-roll cold rolling mill, rolling the semi-finished product with a specification of Ф57×4.5mm into a semi-finished product with a specification of Ф38×3.0mm; Pass 2: Roll the semi-finished product with a specification of Ф38×3.0mm into a finished product with a specification of Ф13.7×1.2mm by using a two-roll high-speed rolling mill. 9. The pipe-making method for reducing surface defects of pure nickel cold-rolled seamless pipes according to claim 8, characterized in that: in the pass 0, the rolling speed of the two-roll cold rolling mill is 60-70 times/ minutes, the pass gap is 0.3-1.0mm, the rolling gap is 1.5-3.8mm, the feed rate is 3-6mm, the corner is 41.5-42.2 degrees, the lubrication method is online large-flow thin oil lubrication, and the billet is added before rolling Re-inspection, re-inspection of pass type after rolling three pipes; In said pass 1, the rolling speed of the two-roll cold rolling mill is 68-80 times/minute, the pass gap is 0.2-1.0mm, the rolling gap is 1.5-3.2mm, and the feed rate is 3-6mm. The rotation angle is 41.5-42.2 degrees, and the lubrication method adopts online large-flow thin oil lubrication; In the pass 2, the rolling speed of the two-roller high-speed rolling mill is 110-140 times/min, the pass gap is 0.15-0.5 mm, the rolling gap is 1.2-2.8 mm, the feed rate is 3.5-5 mm, and the corner The inlet end is 31.0 degrees, and the outlet end is 26.0 degrees. The lubrication method adopts the combination of online large-flow thin oil external lubrication and special rolling lubricant mandrel tail high-pressure input internal lubrication.

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