CN102154599B - Short-flow high-efficiency production method for white brass alloy pipes - Google Patents

Abstract

The invention discloses a short-process and high-efficiency production method for cupronickel alloy pipes, which belongs to the field of metal materials. The white copper pipe produced by the hot-cold combined casting mold horizontal continuous casting process is used as the billet. For the production process of the white copper straight pipe, the pipe blank is directly cold-rolled, the total deformation is 50% to 90%, and the single pass deformation is ≤20% to 25. %. For the production process of white copper coils, the tube blank is subjected to cold rolling deformation with a total deformation of ≤50% to 70%, and the deformation in a single pass is ≤20% to 25%. After rolling, low temperature recovery annealing is performed at a temperature of 300 to 550 ℃, annealing time 1~2h, annealing protective atmosphere 2%H ₂ + balance N ₂ , the annealed coil billet needs to be finished by serial drawing or triple drawing before coiling, and the subsequent coiling process, the average The pass extension coefficient is 1.2~1.5, and the coil pulling speed is 1~1000m/min. Compared with the production of white copper pipes by the traditional casting-rolling-drawing method, the invention has a shorter process flow, significantly reduced annealing times and lower annealing temperature, which is beneficial to save energy and improve production efficiency.

Description

A short-process and high-efficiency production method for cupronickel alloy pipes

technical field

The invention belongs to the field of metal materials, and relates to a short-process and high-efficiency preparation method for white copper pipes, in particular to a short-process preparation method for thin-walled white copper straight pipes and coil pipes.

Background technique

The production of white copper alloy pipes at home and abroad mainly adopts the pipe-making process of "semi-continuous casting solid ingot-hot extruded tube billet-cold rolling-drawing" (referred to as extrusion-rolling method). , plus peeling, pickling, intermediate annealing and other processes, the total processing procedure is as many as more than 20 passes [see: Guo Li, Li Yaoqun, Condenser Tube Production Technology, P.30-32, Metallurgical Industry Press, 2007 ], leading to a series of problems such as long process flow, high energy consumption, low yield and high cost.

The use of advanced short-flow process to produce cupronickel alloy pipes has become the focus and direction of research and development in recent years. The current research is mainly focused on the direct preparation of white copper tube blanks by continuous casting, replacing the traditional "semi-continuous casting solid ingot-hot extrusion tube blank" process, combined with subsequent processing and forming, to produce different specifications. Cupronickel straight and coiled tubes.

Among them, the "cast-rolling method" (horizontal continuous casting hollow tube billet-surface milling, inner surface brush milling-planetary rolling/cold rolling-disc pulling or straight pulling production process, referred to as casting-rolling method) is characterized by the use of The common horizontal continuous casting process prepares the tube billet. Since the inner and outer surfaces of the continuous casting billet are prone to defects such as orange peel, segregation, microcracks, and wrinkles, the inner and outer surfaces must be milled before the subsequent processing of the billet. On the one hand, it increases the process and reduces the yield. On the other hand, defects on the inner surface of the tube blank (such as wrinkles on the inner surface) can only be brushed and milled (polished) with a wire brush, which is difficult to effectively eliminate, and is brought into the subsequent processing process, which seriously affects the quality of the product. In addition, the ordinary horizontal continuous casting billet is a well-developed radial columnar grain structure with low density, which is not conducive to the axial extension deformation of subsequent cold working (rolling, drawing).

Adopt the production method of "preparation of small-diameter thin-walled tube billet by continuous directional solidification - straight drawing or coil drawing" [see: Xie Jianxin et al., Short-process preparation process of copper and copper alloy precision pipes, Chinese invention patent, ZL200710065281.9, 2009- 06-10], high-quality pipes with continuous columnar crystal structure can be prepared, but the diameter and wall thickness of the prepared pipes are small, and the continuous casting speed is slow, which is only suitable for small batch production of high-quality white copper pipes, and it is difficult to meet large Large-scale industrial production needs. the

The hot-cold combination casting mold horizontal continuous casting invented by the applicants of the present invention [See: Xie Jianxin et al., A kind of heat-cooling combination casting mold horizontal continuous casting process and equipment for white copper pipe, Chinese invention patent, application number 201010501407.4, application date 2010- 10-09] is a newly developed new high-efficiency continuous casting process for large-diameter white copper pipes. The internal and external surfaces of the pipe are of high quality, and can be directly cold-formed without milling; the pipe has a columnar grain structure with a high degree of axial orientation, which is very conducive to the axial extension and deformation of subsequent cold processing (such as rolling, drawing).

Therefore, the hot-cold combined mold horizontal continuous casting provides a new way for the short-process and high-efficiency production of white copper pipes. Based on this invention patent, a short-process and high-efficiency production method for copper alloy pipes can be developed.

Contents of the invention

The purpose of the present invention is to solve the problems of long technological process and low yield of white copper pipes in the existing production method of white copper pipes, to provide high-quality white copper pipes with high efficiency, increase the yield of finished products, and reduce production costs. Combined with a specific forming process and annealing process, it is a short-flow and high-efficiency production method for white copper pipes.

A short-process and high-efficiency production method for white copper alloy pipes, the specific steps are as follows:

Step 1: Prepare a BFe10 white copper tube billet with a diameter of Ф50-120mm and a wall thickness of 3-20mm by horizontal continuous casting of hot and cold combined molds;

Step 2: According to the difference between the two types of straight tube and coiled tube products, two different subsequent processing techniques are adopted: (1) During the production process of white copper straight tube, the tube blank described in step 1 can be directly cold-rolled, The total deformation is 50% to 90%, and the single pass deformation is ≤20% to 25%. During the rolling process, intermediate annealing or low temperature annealing can be carried out, so that the pipe can eliminate work hardening and maintain the structure along the axial direction. Conducive to subsequent processing, the annealing temperature is 300-550°C, and the annealing time is 1-2 hours; the diameter of the white copper cold-rolled straight pipe that can be produced according to the above process is Ф15-45mm, the wall thickness is 0.5-2.5mm, and the length of the finished straight pipe is ≤15m. (2) In the production process of white copper coil pipe, the tube blank is subjected to cold rolling deformation with a total deformation of ≤50% to 70%, and the deformation in a single pass is ≤20% to 25%. Intermediate annealing may not be performed during the rolling process, and the rolling is completed Afterwards, low temperature recovery annealing is carried _out to ensure that the pipe has good cold working performance and maintains _the orientation structure. The tube billet needs to be finished by serial drawing or triple drawing before coil drawing. In the subsequent coil drawing process, the average pass elongation coefficient is 1.2~1.5, the coil drawing speed is 1~1000m/min, and the diameter of cupronickel coil tubes can be produced 50mm, wall thickness 0.5~3mm, coil weight 400~700Kg.

Step 3: Perform bright annealing on the finished pipe formed in step 2 as required, mainly to change the processing structure and obtain the required performance, and make the product have a bright surface state to meet the use requirements of the product. After the pipe reaches the finished product size, the annealing process is formulated according to the type of annealing equipment, pipe size, supply status, etc. Generally, the annealing temperature of soft products is 690-750°C, and the annealing time is 40-60min; the annealing temperature of semi-hard products is 550-740°C, and the annealing time 40~60min, annealing protective atmosphere 2%H ₂ + balance N ₂ .

The advantages of the present invention are:

1. The white copper pipe produced by the hot-cold combined mold horizontal continuous casting process is used as the billet. Due to the high quality of the inner and outer surfaces of the billet, subsequent rolling can be directly carried out without milling, which reduces the process and improves the yield;

2. The subsequent processing technology of the production method provided by the present invention is conducive to significantly improving production efficiency compared with the traditional production method of white copper pipes. The tube billet used in the traditional casting-rolling-drawing method has a well-developed radial columnar grain structure. Due to the poor plastic processing performance of this kind of tube billet, it can be continuously cold-worked without annealing, and the deformation amount is small, so the production efficiency is relatively low. Low; while the tube blank used in the present invention has an axially oriented structure, and can maintain good plastic working ability without intermediate annealing during the axial extension process (rolling and coil drawing), so the production efficiency high.

3. Compared with the production method of white copper pipes produced by the traditional cast-rolling method, the production method provided by the present invention significantly reduces the number of annealing times and the annealing temperature, and even does not require intermediate annealing, so it is not only more conducive to saving energy, but also conducive to improving production. efficiency.

Detailed ways:

Example 1: Production method of B10 white copper straight tube (soft state) with a size of Ф50×5mm

①Using hot-cold combination casting horizontal continuous casting to prepare tube blanks with a diameter of Ф70×8mm, the melting temperature of molten copper is 1250°C, the holding temperature is 1200°C, the temperature of the hot mold (mold heating) is 1200°C, and the cooling water of the cold mold (water-cooled copper sleeve) The flow rate is 600L/h, and the traction speed is 150mm/min.

②The tube blank prepared in step 1 is subjected to three-pass three-roller periodic cold rolling, with an average deformation of 20%, and the deformation of each pass gradually decreases with the increase of cumulative deformation. Intermediate annealing may not be performed.

③Bright annealing is carried out on the pipe after rolling. The annealing temperature is 730°C, the annealing time is 50min, and the annealing protective atmosphere is 2%H ₂ + balance N ₂ .

Example 2: Production method of B10 white copper straight tube (semi-hard state) with a size of Ф20×1mm

①Using hot-cold combination casting horizontal continuous casting to prepare tube blanks with a diameter of Ф50×5mm, the melting temperature of copper liquid is 1250°C, the holding temperature is 1200°C, the temperature of hot mold (mold heating) is 1200°C, and the cooling water of cold mold (water-cooled copper sleeve) The flow rate is 600L/h, and the traction speed is 150mm/min.

② The tube blank prepared in step 1 is subjected to 8 passes of three-roller periodic cold rolling, with an average deformation of 20%, and the deformation of each pass gradually decreases with the increase of the cumulative deformation. Intermediate annealing may not be performed.

③Bright annealing is carried out on the pipe after rolling. The annealing temperature is 550°C, the annealing time is 50min, and the annealing protective atmosphere is 2% H ₂ + the balance N ₂ .

Example 3: Production method of B10 nickel-copper coil (soft state) with a size of Ф15×1mm

①Using hot-cold combination casting horizontal continuous casting to prepare tube blanks with a diameter of Ф50×5mm, the melting temperature of copper liquid is 1250°C, the holding temperature is 1200°C, the temperature of hot mold (mold heating) is 1200°C, and the cooling water of cold mold (water-cooled copper sleeve) The flow rate is 700L/h, and the traction speed is 200mm/min.

② Carry out large-deformation planetary rolling on the tube blank prepared in step 1, and the deformation amount is 40-50%.

③ The rolled tube blank is subjected to 1-3 passes of series drawing or triple drawing, with a deformation of 15% to 25%, the purpose of which is to finish the pipe before coil drawing.

④ Perform low temperature recovery annealing on the finished tube blank, the annealing temperature is 400°C, the annealing time is 1h, and the annealing protective atmosphere is 2% H ₂ + balance N ₂ .

⑤ Pull the tube blank after low temperature recovery annealing, the average pass elongation coefficient is 1.3, the stretching pass is 3 to 4 passes, and the drawing speed is 500m/min.

⑥Perform bright annealing on the coiled pipe, the annealing temperature is 700°C, the annealing time is 40min, the annealing protection atmosphere is 2%H ₂ + balance N ₂ , the purpose is to obtain the finished pipe in a soft state, and the performance meets the requirements for use.

Example 4: Production method of B10 nickel-copper coil (semi-hard) with a size of Ф20×0.75mm

①Using hot-cold combination casting horizontal continuous casting to prepare tube blanks with a diameter of Ф50×5mm, the melting temperature of copper liquid is 1250°C, the holding temperature is 1200°C, the temperature of hot mold (mold heating) is 1200°C, and the cooling water of cold mold (water-cooled copper sleeve) The flow rate is 700L/h, and the traction speed is 200mm/min.

②The tube blank prepared in step 1 is subjected to 3-5 passes of three-roller periodic cold rolling, with an average deformation of 20% and a total deformation of 50% to 60%. The deformation of each pass increases with the total deformation. The increase of the amount gradually decreases, and the rolling process does not require intermediate annealing.

③ The rolled tube blank is subjected to 1-3 passes of series drawing or triple drawing, with a deformation of 15% to 25%, the purpose of which is to finish the pipe before coil drawing.

④ Perform low-temperature recovery annealing on the finished tube blank, the annealing temperature is 400°C, and the annealing time is 1h.

⑤ Pull the tube blank after low temperature recovery annealing, the average pass elongation coefficient is 1.3, the stretching pass is 3 to 4 passes, and the drawing speed is 500m/min.

⑥Perform bright annealing on the coiled pipe. The annealing temperature is 550℃, the annealing time is 40min, and the annealing protection atmosphere is 2%H ₂ + balance N ₂ .

Claims (1)

1. A kind of short process high-efficiency production method of cupronickel alloy pipe material is characterized in that concrete steps are as follows: Step 1: Prepare a BFe10 white copper tube billet with a diameter of Ф50-120mm and a wall thickness of 3-20mm by horizontal continuous casting of hot and cold combined molds; Step 2: According to the difference between the two types of straight pipe and coil pipe products, two different subsequent processing techniques are adopted: (1) In the production process of white copper straight pipe, the tube blank described in step 1 is directly cold-rolled, with a total deformation of 50% to 90%, and a single pass deformation of 20% to 25%; no intermediate annealing is performed during the rolling process; The diameter of the white copper cold-rolled straight pipe that can be produced according to the above process is Ф15-45mm, the wall thickness is 0.5-2.5mm, and the length of the finished straight pipe is ≤15m; (2) In the production process of white copper coil pipe, the tube blank is subjected to cold rolling deformation with a total deformation of 50% to 70%, and the deformation in a single pass is 20% to 25%. Intermediate annealing is not performed during the rolling process, and the rolling is carried out after the rolling is completed. Low temperature recovery annealing to ensure that the pipe has good cold working performance and maintains the orientation structure. The annealing temperature is 300-550 ° C, the annealing time is 1-2 hours, the annealing protective atmosphere is 2% H ₂ + the balance N ₂ , and the coiled tube blank after annealing The finishing before coil drawing needs to be done once by serial drawing or triple drawing. In the subsequent coil drawing process, the average pass elongation coefficient is 1.2~1.5, and the coil pulling speed is 1~1000m/min. It can produce cupronickel coils with a diameter of Ф5~50mm. Wall thickness 0.5~3mm, coil weight 400~700Kg; Step 3: Perform bright annealing on the finished pipes formed in Step 2 as required to change the processing structure and obtain the required performance, and make the product have a bright surface state to meet the requirements of the product; after the pipe reaches the finished product size, according to The annealing process is determined by the type of annealing equipment, pipe size, and supply status. The annealing temperature for soft products is 690-750°C, and the annealing time is 40-60 minutes; the annealing temperature for semi-hard products is 550-740°C, and the annealing time is 40-60 minutes. H ₂ + balance N ₂ .