CN106695173B - A kind of welding material for welding titanium-steel composite plate near titanium layer and preparation method thereof - Google Patents

Abstract

The invention discloses a welding material for welding the near-titanium layer of a titanium-steel composite plate and a manufacturing method thereof. The composition of the welding material is: C≤0.02%, Si≤0.02%, Mn3.2-3.38% in terms of mass percentage , P≤0.02%, S≤0.01%, Cr 13‑15%, Cu 0.012‑0.014%, Fe≤0.7%, Ti 0.3‑0.52, Co 0.032‑0.038%, Nb+Ta 1.9‑3%, the balance is Ni. Using this welding material to weld the transition layer from the titanium layer to the steel layer avoids the generation of intermetallic compounds, and can effectively realize the fusion welding transition of the titanium layer and the near titanium layer of the titanium-steel composite pipe; the diameter of the welding wire of the present invention is as small as 1.2mm, not only can be welded by manual tungsten argon arc welding and metal argon arc welding, but also the welding wire of the invention has simple manufacturing process, low cost, and is convenient for large-scale batch production.

Description

A kind of welding material for welding titanium-steel composite plate near titanium layer and preparation method thereof

Technical field:

The invention belongs to the technical field of metal material welding, and in particular relates to a welding material for welding a near-titanium layer of a titanium-steel composite plate and a preparation method thereof.

Background technique:

The titanium-steel bimetallic composite material realizes the perfect metallurgical combination of different metals with widely different strengths, melting points, and thermal expansion coefficients, and gives full play to the characteristics of different materials. It not only solves the corrosion resistance requirements of oil and gas transportation pipelines, but also solves the High strength and toughness requirements for pipelines.

At present, the butt joint of titanium-steel composite plates is welded first, and then the titanium plate is welded separately in the form of a cover plate, thus avoiding the eutectic pool welding of the two materials, but the joint structure of this welding method is complicated and the strength is insufficient. , it is difficult to apply engineering on the pipeline. However, due to the great difference in the crystallization chemical and thermophysical properties of titanium and iron, if they are directly welded in the same molten pool, it is easy to form intermetallic compounds, which will cause cracks in the weld, and the plasticity and toughness of the welded joint will deteriorate, which seriously hinders Large-scale application of titanium-steel composite panels. In this regard, we researched and proposed a welding method that uses different welding materials and welds titanium-steel composite plates in a certain order. Among them, the welding materials of the titanium layer and the steel layer are relatively mature, but the transition layer from titanium to steel Among the welding materials, the near-titanium layer welding materials are not yet mature.

The authorized announcement number of June 22, 2016 is the Chinese invention patent of 103567660B, which is called the welding method for welding the transition layer of titanium-pipeline steel composite plate. The welding material near the titanium layer is composed of the following components: Ni52-58 %, C ≤ 0.04%, N ≤ 0.007%, O ≤ 0.035%, H ≤ 0.001%, the balance is Ti; the welding material near the steel layer is composed of the following components: Mn3.15-3.35%, Cr18-27%, Cu0.01-0.015%, Ti0.35-0.55%, Co0.03-0.04%, Nb1.8-2.0%, Ta0.2-0.6%, C≤0.02%, Si≤0.025%, P≤0.002%, S≤0.002%, Fe≤0.75%, and the balance is Ni. The high content of Cr in this patent will reduce the strength and hardness of the welded joint, and the low content of S and P is not conducive to production control and increases production cost.

The Chinese invention patent with the application number 201610224395.2 filed on April 12, 2016, is a method for preparing TIG/MIG welding wire of high-purity aluminum-silicon alloy SAL4043 for high-speed trains. The method includes Si, Fe, Mg, Cu, Sc and Al are smelted in a vacuum induction furnace according to a certain ratio; after the materials are melted, add a grain refiner to stir, and after the melt is cleared, add a refining agent to degas and refine, and after standing still, remove the slag , out of the furnace; after removing the sundries on the surface of the ingot and at both ends, the alloy wire rod is obtained by rolling continuous extrusion; after the alloy wire rod is rough drawn, middle drawn, annealed, and finely drawn, it is scraped and cleaned. The welding wire and the specific process parameters in the manufacturing method are not suitable for the preparation of the welding material of the present invention.

Invention content:

The object of the present invention is to provide a kind of welding material and preparation method thereof for welding titanium-steel clad plate near titanium layer, use this welding material to weld the transition layer from titanium layer to steel layer, avoid the generation of intermetallic compound, weld seam The combination is better.

In order to solve the above-mentioned technical problems, the technical solution adopted in the present invention is: a welding material for welding the titanium-steel composite plate near the titanium layer, the composition of the welding material is: C≤0.02%, Si≤0.02%, Mn3.2-3.38%, P≤0.02%, S≤0.01%, Cr 13-15%, Cu 0.012-0.014%, Fe≤0.7%, Ti 0.3-0.52, Co 0.032-0.038%, Nb+Ta 1.9- 3%, the balance is Ni.

The above welding material is wire welding with a diameter of 1.2 mm.

The effect of basic element contained in the welding material of welding titanium-steel clad plate of the present invention near titanium layer and the selection of consumption thereof are specifically analyzed below:

Carbon (C): If the C content in the welding material is too high, it will form hard and brittle TiC with titanium, which is prone to cracks. Therefore, the C content is preferably ≤0.02%.

Iron (Fe): Fe can reduce the phase transition point, stabilize the β phase, significantly enhance the strength of the weld, control the appropriate content of Fe element, and will not form Ti Fe phase in the weld structure, so the Fe content is preferably ≤0.7 %.

Cobalt (Co): The addition of Co element helps to suppress and reduce the diffusion of Cu and Ni elements to the base material and improve joint performance, so the Co content is preferably 0.032-0.038%.

Chromium (Cr): Excessive Cr content will reduce the strength and hardness of the material. When the Cr content exceeds 15%, it will form an intermetallic compound (σ phase) with iron, which will cause a huge volume change in the solid solution and cause large stress. Therefore, it is very brittle; C and Cr are easy to form free ferrite (δ), which will reduce the heat resistance of the material. Reasonable control of Cr content can reduce the δ phase, so the Cr content is preferably 13-15%.

Silicon (Si), manganese (Mn): Si and Mn are strong deoxidizers, so the content is relatively high. Oxygen in the molten pool forms compounds with Si and Mn to avoid CO generation. The weld pores are small, and Mn and S form MnS eliminates the harmful effect of S, so the preferred Si content is ≤0.025%, and the preferred Mn content is 3.2-3.38%.

Nb+Ta: Nb+Ta element can play the role of solid solution strengthening, the content is 1.9-3%;

Phosphorus (P), sulfur (S): When S changes in the range of 0.007% to 0.04%, the change of structure is related to the MnS layer formed on the surface of the inclusion, the hardness and strength of the weld metal are reduced, and the impact toughness is seriously deteriorated. When P changes in the range of 0.007% to 0.04%, it has no obvious effect on the weld structure. When the content of S and P in the weld metal is lower than 0.005%, reducing the content of S and P has little effect. S and P are restrictive impurity elements, but reducing the content of S and P indefinitely will inevitably lead to an increase in production cost, so the content of S and P is controlled to be S≤0.01%, P≤0.02%.

The manufacturing method of the welding material near the titanium layer of the above-mentioned welding titanium-steel clad plate comprises the following steps:

Step 1: weighing each element according to the mass percentage of the welding material composition, putting the weighed Ni, Cr, Nb, Ta, and Fe elements into a vacuum induction melting furnace for melting and refining in sequence to form molten steel, The refining temperature is 1400-1600°C and the time is 25min;

Step 2: After refining, pour argon gas into the vacuum induction melting furnace. The content of the filled argon gas is 300-350mmHg. After the argon gas flushing is completed, add the remaining metal elements into the molten steel for stirring, and finally cast to form a casting For ingots, the temperature of molten steel during casting is 1500°C;

Step 3: forging, rolling and drawing the cast ingot in sequence to form the welding material for welding the titanium-steel composite plate near the titanium layer.

The specific process of sequentially forging, rolling and drawing the ingot in the above step three is as follows: firstly, the ingot is forged into a 50mm×50mm square billet at 1100-1150°C by using a double-armed electric air hammer; The 200-type five-stand three-roll rolling mill rolls the billet into Φ6.5mm wire rod at 1000-1200℃; finally, the Φ6.5-Φ7.0mm wire rod is subjected to mechanical peeling-acid washing-drying in sequence -Dry wire drawing-coiling-heat treatment-dry wire drawing-coiling-polishing-coiling-winding and other step-by-step drawing to form welding materials for welding titanium-steel composite plates near the titanium layer.

Beneficial effects of the present invention:

Use the welding material of the present invention to weld the V-shaped groove of the titanium-steel composite plate, first weld the titanium layer with the titanium welding material, and then use the welding material of the present invention to weld the transition near the titanium layer, which can effectively realize the titanium-steel composite pipe The titanium layer and the near-titanium layer are welded and transitioned; the diameter of the welding material of the present invention is small, not only can be welded by manual argon tungsten arc welding and argon metal arc welding, but also the manufacturing process of the welding material of the present invention is simple and the cost is low , which is convenient for large-scale mass production.

Description of the drawings:

The specific embodiments of the present invention will be further described in detail below in conjunction with the specific embodiments.

Fig. 1 is a metallographic diagram of the deposited metal in Example 1 of the present invention.

Fig. 2 is a SEM image of the deposited metal in Example 1 of the present invention.

Fig. 3 is a metallographic diagram of the deposited metal in Example 2 of the present invention.

Fig. 4 is a SEM image of the deposited metal in Example 2 of the present invention.

Detailed ways:

Example 1:

First, purify various high-purity metals, according to the weight percentage of each element: C 0.02%, Si0.18%, Mn 3.25%, P 0.005%, S 0.005%, Cr 13%, Cu 0.013%, Fe 0.5% , Ti 0.51%, Co0.035%, Nb+Ta 2.4%, the balance is Ni, weigh each metal element respectively, and put the weighed Ni, Cr, Fe, Nb, Ta materials into the vacuum induction melting furnace Melt in a MgO crucible, and turn to refining when all the metal in the furnace is melted and the surface of the molten pool is calm without bubbles escaping. The refining temperature is 1400-1600 ° C, and the refining time is 25 minutes; 1500°C, fill the furnace with argon to make the furnace reach 300-350mmHg, then add the pre-weighed Mn, Cu, Ti, Co metal materials into the molten steel, stir for 2 minutes before casting, and the tapping temperature during casting is 1500°C; Pouring is heated with a small power. During the pouring process, the surface of the molten steel is calm and the pouring is even. After the pouring is completed, the ingot mold is stored in a vacuum chamber for half an hour, and the ingot is taken out and cooled to room temperature. During the smelting process, the contents of C, Si, P, and S are controlled as follows: C≤0.02%, Si≤0.02%, P≤0.02%, S≤0.01%.

Use double-arm electric air hammer (750Kg) to forge the ingot into a 50mm×50mm square billet at 1100-1150°C, and then roll the billet at 1000-1200°C with a 200-type five-stand three-roll mill. into Φ6.5mm wire rod; the wire rod is drawn step by step through mechanical peeling-pickling-drying-dry wire drawing-coiling-heat treatment-dry wire drawing-coiling-polishing-coiling-winding, etc., and finally A welding wire of Φ1.2mm is formed.

Cut a titanium-steel composite plate with a specification of 160×180×16mm, open a V-shaped 60° groove on one side and both sides, use TC4 titanium wire and the welding wire of the present invention to weld the titanium layer and the near-titanium layer respectively, and weld the titanium layer first layer, then weld near titanium layer, near steel layer, and then weld steel layer; the welding method and welding process are shown in Table 1. The mechanical properties of the welded joints are shown in Table 2. SEM tests and metallographic experiments were carried out on the welded joints. The metallographic structure of the weld center is shown in Figure 1, and the SEM image is shown in Figure 2.

Table 1 welding method and welding process parameters

Titanium layer transition layer steel layer Welding method Manual tungsten arc welding MIG CO2 gas shielded welding Welding current 85～110A 90～125A 150～175A welding voltage 14～15V 12～14V 14～18V

Table 2 Mechanical properties of welded joints

As can be seen from Figure 1, the TC4 welding wire of the titanium layer is well combined with the welding wire structure of the near-titanium layer of the present invention. The average length is about 50 μm; the near-titanium layer is organized as smaller equiaxed grains on the side close to TC4, and the grain size is basically the same as that of the TC4 structure; the transition between the titanium layer-near-titanium layer interface is smooth, and no The transition zone or interface line, it can be seen that the two-layer weld has achieved a good metallurgical bond.

It can be seen from Figure 1 that the microstructure of the near-titanium layer and the near-steel layer of the sample have been extended and expanded, and the microstructure of the near-titanium layer and the near-steel layer Ni-Cr alloy crystallized is intricately intertwined. It can be clearly seen that the microstructure of the near-titanium layer has changed from The equiaxed microstructure close to the TC4 layer turns into fine strips and small block ferrite microstructure, and the Ni-Cr microstructure of the nickel-based alloy layer near the titanium layer presents divergent dendritic grains.

It can be seen from the scanning electron microscope in Figure 2 that the near-titanium layer is well combined with the Ni-Cr layer, and there are no defects such as cracks and inclusions.

Example 2:

First, purify various high-purity metals, weigh them separately according to weight percentage, and then according to the weight percentage of each element: C 0.02%, Si 0.15%, Mn 3.3%, P 0.001%, S 0.002%, Cr 14%, 0.012% Cu, 0.6% Fe, 0.38% Ti, 0.037% Co, 2.2% Nb+Ta, the balance being Ni, weighing each metal element respectively;

Cut a titanium-steel composite plate with a specification of 160×180×16mm, open a V-shaped 60° groove on one side and both sides, use TC4 titanium wire and the welding wire of the present invention to weld the titanium layer and the near-titanium layer respectively, and weld the titanium layer first layer, then weld near titanium layer, near steel layer, and then weld steel layer; the welding method and welding process are shown in Table 3. The mechanical properties of the welded joints are shown in Table 4. Metallographic experiments were carried out on the welded joints. The metallographic structure of the weld center is shown in Figure 3, and the SEM image is shown in Figure 4.

Table 3 welding method and welding process parameters

Table 4 Mechanical properties of welded joints

It can be seen from Fig. 3 that the TC4 welding wire of the titanium layer is well combined with the welding material interface near the titanium layer of the present invention, and the two-layer structures are irregular equiaxed crystals, which is also due to the same thermal history and similar composition of the two layers. ; After the crystallization of the near-titanium layer, a pentagonal equiaxed structure is formed.

It can be seen from Figure 3 that the microstructure of the near-titanium layer and the near-steel layer of the sample are relatively similar in appearance, the microstructure of the near-titanium layer and the near-steel layer after Ni-Cr alloy crystallization are intricate, and the microstructure of the near-titanium layer has changed from that of the near-titanium layer to that of the near-titanium layer. The axis structure becomes thin strip dendrites, and the leaf-like grains of different widths and lengths are distributed around the dendrites, and the branches extend deeper to the nickel-based alloy layer and the nickel-based alloy layer forms a wider transition zone.

It can be seen from the scanning electron microscope in Figure 4 that the near-titanium layer is well bonded to the Ni-Cr layer, and there are no defects such as cracks and inclusions.

Claims (1)

1. a kind of manufacturing method for the welding material for welding the nearly titanium layer of titanium-steel composite board, it is characterised in that: the welding material Ingredient is according to mass percent are as follows: C:0.02%, Si:0.18%, Mn:3.25%, P:0.005%, S:0.005%, Cr: 13%, Cu:0.013%, Fe:0.5%, Ti:0.51%, Co:0.035%, Nb+Ta:2.4%, surplus Ni；The welding material Material is the wire bond that diameter is 1.2mm；

The manufacturing method the following steps are included:

Step 1: weighing each element according to the mass percent of the welding material ingredient respectively, by weighed Ni, Cr, Nb, Ta, Fe element, which are put into vacuum induction melting furnace, successively to be melted, is refined, and molten steel is formed, and the temperature of the refining is 1400-1600 DEG C, time 25min；

Step 2: to argon gas is filled in vacuum induction melting furnace after refining, the content for being filled with argon gas is 300-350mmHg, argon gas Remaining element is added in molten steel after the completion of pouring and be stirred, is finally cast, ingot casting is formed, the temperature of molten steel is when casting 1500℃；

Step 3: successively forging ingot casting, rolled and drawing, and the welding of the nearly titanium layer of the welding titanium-steel composite board is formed Material；

Ingot casting is successively forged in the step 3, is rolled and drawing specifically comprises the processes of: first using double-arm electronic Ingot casting is forged into the square billet of 50mm × 50mm by pneumatic hammer at 1100-1150 DEG C；Secondly 200 type, five frame row three is used Square billet is rolled into Φ 6.5mm wire rod at 1000-1200 DEG C by roller mill；Successively to Φ 6.5- Φ 7.0mm wire rod finally Carry out mechanical descaling-pickling-drying-dry method is hot candied-batch-be heat-treated-dry wire drawing-is batched-polish-batching-wind etc. by Grade drawing, forms the welding material for welding the nearly titanium layer of titanium-steel composite board；

Titanium-steel composite board, 60 ° of grooves of unilateral double open V-arrangement, titanium layer, transition zone are welded using TC4 titanium silk and the welding material Hand tungsten argon arc welding, metal argon arc welding and CO are successively used with steel layer₂Gas shielded arc welding, hand tungsten argon arc welding, fusing Electrode argon arc welding and CO₂The weldingvoltage of gas shielded arc welding is followed successively by 14-15V, 12-14V and 14-18V, and welding current is followed successively by 85-110A, 90-125A and 150-175A；The mechanical property of welding point: tensile strength 498MPa, yield strength 395MPa break Elongation percentage 12.5% afterwards, expansion and contraction 35.5% of having no progeny, the impact flexibility 35J under room temperature；Nearly titanium layer has occurred with nearly steel layer tissue Extend and extension, nearly titanium layer organize crisscross intertexture after crystallizing with nearly steel layer Ni-Cr alloy, nearly titanium layer tissue is by close to TC4 layers Equiaxed structure become slice and small block-like ferritic structure, nickel base alloy layer Ni-Cr is being in close to nearly titanium layer side tissue The dendroid crystal grain of diverging.