阅读说明：本技术 一种铝或铝合金镀层热成型钢的拼焊制造方法 (Tailor-welding manufacturing method of aluminum or aluminum alloy coating hot-formed steel ) 是由 王小杰 冯浩宇 韩振宇 刘春景 于 2019-09-17 设计创作，主要内容包括：一种铝或铝合金镀层热成型钢的拼焊制造方法,按照下列步骤进行：a、将铝或铝合金镀层热成型钢板料待焊接部位的合金层、过渡层全部去除,同时去除部分基材,构成基材凹槽；b、根据基材成分及基材凹槽深度选取焊丝；c、利用激光填丝焊方式对热成型板料进行焊接；d、将焊接完成的产品件进行淬火。本发明方法既保证了镀层金属不会进入熔池,也保证了填充金属能最大限度的覆盖剥离部位,而且能有效防止边部镀层金属随焊接热循环熔化进入熔池；此外,在保证焊接质量的同时,具有工艺过程容易实施,适合大规模生产制造应用,能保证批量生产的稳定性的特点。(A tailor-welding manufacturing method of aluminum or aluminum alloy coated hot-formed steel comprises the following steps: a. completely removing an alloy layer and a transition layer of a part to be welded of the aluminum or aluminum alloy coating hot-formed steel plate material, and simultaneously removing a part of base material to form a base material groove; b. selecting welding wires according to the components of the base material and the depth of the groove of the base material; c. welding the hot-formed plate by using a laser wire filling welding mode; d. and quenching the welded product pieces. The method of the invention not only ensures that the plating metal can not enter the molten pool, but also ensures that the filling metal can cover the stripping part to the maximum extent, and can effectively prevent the plating metal at the edge part from melting into the molten pool along with the welding thermal cycle; in addition, the welding quality is ensured, and meanwhile, the method has the characteristics that the technological process is easy to implement, the method is suitable for large-scale production and manufacturing, and the stability of batch production can be ensured.)

1. a tailor-welding manufacturing method of aluminum or aluminum alloy coated hot-formed steel is characterized by comprising the following steps:

a. completely removing an alloy layer and a transition layer of a part to be welded of the aluminum or aluminum alloy coating hot-formed steel plate material, and simultaneously removing a part of base material to form a base material groove;

b. selecting welding wires according to the components of the base material and the depth of the groove of the base material;

c. welding the hot-formed plate by using a laser wire filling welding mode;

d. and (3) keeping the temperature of the welded product piece at 930-950 ℃ for 300s, and quenching at a cooling speed of more than 30 DEG/s.

2. The tailor welded manufacturing method of an aluminum or aluminum alloy coated hot-formed steel according to claim 1, wherein: the welding wire components are determined according to the components of the base material and the depth of the groove of the base material: the welding wire comprises C, Si, Mn, S, P and Fe, wherein the percentage content of the C, Si and Mn elements is 0.8-1.2 times of the percentage content of the C, Si and Mn elements in the base material; the percentage content of the P and S elements in the welding wire composition does not exceed the percentage content of the P and S elements in the base material composition; when the depth of the groove of the base material is more than 30 μm, 0.002-0.012% of B element is added into the welding wire component.

3. The tailor welded manufacturing method of an aluminum or aluminum alloy coated hot-formed steel according to claim 2, wherein: the welding wire also comprises 0.01-0.1% of Cr and 0.01-0.1% of Ni.

4. The tailor welded manufacturing method of an aluminum or aluminum alloy coated hot-formed steel according to claim 3, wherein: the depth of the base material groove is 2-100 μm, and the width W of the base material groove is 0.5-3 mm.

5. The tailor welded manufacturing method of an aluminum or aluminum alloy coated hot-formed steel according to claim 4, wherein: the depth of the base material groove is 10-50 μm, and the width W of the base material groove is 1-1.5 mm.

6. The tailor welded manufacturing method of an aluminum or aluminum alloy coated hot-formed steel according to claim 5, wherein: the cross section of the groove is rectangular or curved.

7. The tailor welded manufacturing method of an aluminum or aluminum alloy coated hot-formed steel according to claim 6, wherein: the alloy layer, the transition layer and the base material are removed in a laser, plasma arc or water jet mode, and are removed vertically or at a certain angle with the coating and the base material.

8. The tailor welded manufacturing method of an aluminum or aluminum alloy coated hot-formed steel according to claim 7, wherein: the thickness of the coating of the aluminum or aluminum alloy coating hot forming steel is 8-35 microns.

Technical Field

The invention relates to a metal tailor-welding method, in particular to a tailor-welding manufacturing method of aluminum or aluminum alloy coating hot forming steel.

Background

The bare-plate hot-formed steel forms a large amount of scale after hot stamping, and although the scale can be removed by the shot blasting process, the dimensional accuracy of the part is greatly affected. The development of the aluminum or aluminum alloy coating hot forming steel successfully solves the problems, but the steel products have the following difficulties in laser tailor-welding: the aluminum or aluminum alloy coating can enter a molten pool along with the welding process to form a ferrite phase with lower strength, so that the mechanical property of the tailor-welded joint can not meet the quality requirement. Therefore, in the laser welding process, a proper technical means is adopted to inhibit the harmful effect of the plating metal, and the method is very important for ensuring the good mechanical property of the tailor-welded joint. Patent CN101426612B proposes a method for stripping alloy layer by laser and retaining transition layer to ensure that the welding performance of the coating hot-formed steel meets the quality requirement. However, the method for removing the alloy layer and retaining the transition layer still introduces metal elements of the transition layer in the welding process, and the mechanical property of the welding seam is easily reduced due to improper control; meanwhile, a transition layer of several microns is reserved, and the difficulty of stable implementation of batch production is high. Patent 106334875A proposes a method for stripping alloy layer and transition layer by laser and processing the end face of the plated layer into proper angle, which avoids the aluminum plated layer entering into the molten pool to affect the performance of the joint. The method has great difficulty in stably controlling the angle of the end face of the plating layer, and once the process fluctuates, the subsequent welding process still easily brings aluminum elements into a molten pool, so that the mechanical property of the joint is influenced. In the actual production process, because of the size fluctuation of assembly and weldment, the welding gap is difficult to keep stable during mass production, once the gap is lower than the required range, the harmful effect of aluminum element cannot be inhibited by filling materials, and the performance of a welding joint cannot meet the quality requirement; on the other hand, if the welding gap is too large, the laser energy cannot be sufficiently absorbed by the base material, and the welding stability is impaired. In addition, in order to ensure the austenitization of the weld, excessive austenite stabilizing elements are added to the welding wire composition, which may reduce the hardening tendency of the weld metal and adversely affect the strength of the joint.

Disclosure of Invention

The invention aims to provide a tailor-welding manufacturing method of aluminum or aluminum alloy coating hot-formed steel, which can ensure that the mechanical property of a joint meets the product requirement and the stability of batch production aiming at the defects of the prior art.

The problem of the invention is realized by the following technical scheme:

a tailor-welding manufacturing method of aluminum or aluminum alloy coated hot-formed steel comprises the following steps:

a. completely removing an alloy layer and a transition layer of a part to be welded of the aluminum or aluminum alloy coating hot-formed steel plate material, and simultaneously removing a part of base material to form a base material groove;

b. selecting welding wires according to the components of the base material and the depth of the groove of the base material;

c. welding the hot-formed plate by using a laser wire filling welding mode;

d. and (3) keeping the temperature of the welded product piece at 930-950 ℃ for 300s, and quenching at a cooling speed of more than 30 DEG/s.

According to the tailor-welding manufacturing method of the aluminum or aluminum alloy coating hot forming steel, the welding wire components are determined according to the components of the base material and the depth of the groove of the base material: the welding wire comprises C, Si, Mn, S, P and Fe, wherein the percentage content of the C, Si and Mn elements is 0.8-1.2 times of the percentage content of the C, Si and Mn elements in the base material; the percentage content of the P and S elements in the welding wire composition does not exceed the percentage content of the P and S elements in the base material composition; when the depth of the groove of the base material is more than 30 μm, 0.002-0.012% of B element is added into the welding wire component.

The welding wire for the tailor-welding manufacture method of the aluminum or aluminum alloy coating hot forming steel also comprises 0.01-0.1% of Cr and 0.01-0.1% of Ni.

According to the tailor-welding manufacturing method of the aluminum or aluminum alloy coated hot-formed steel, the groove depth of the base material is 2-100 mu m, and the groove width W of the base material is 0.5-3 mm.

According to the tailor-welding manufacturing method of the aluminum or aluminum alloy coated hot-formed steel, the depth of the groove of the base material is 10-50 mu m, and the width W of the groove of the base material is 1-1.5 mm.

In the tailor-welding manufacturing method of the aluminum or aluminum alloy coating hot-formed steel, the cross section of the groove is rectangular or curved.

In the tailor-welding manufacturing method of the aluminum or aluminum alloy coating hot-forming steel, the alloy layer, the transition layer and the base material are removed in a laser, plasma arc or water jet mode, and are removed vertically or at a certain angle with the coating and the base material.

According to the tailor-welding manufacturing method of the aluminum or aluminum alloy coated hot-formed steel, the coating thickness (including the alloy layer and the transition layer) of the aluminum or aluminum alloy coated hot-formed steel is 8-35 micrometers.

The advantages of the method of the invention over the prior art are as follows: 1. the laser or other high-energy beams are utilized to completely remove the surface layer and the transition layer of the part to be welded and remove part of the base material, thereby completely avoiding the defect that the performance of the joint is reduced because harmful elements in the alloy layer or the transition layer enter a molten pool; 2. welding the two plates by using welding wires with proper components in a wire filling welding mode, effectively controlling and removing the reduction influence of the base material on the thickness of the plates, and simultaneously, remarkably reducing the requirement on the blanking size precision; 3. by removing the base material, a groove is formed on the surface of the base material, molten metal can be spread to two sides of the groove to the maximum extent, and stress corrosion caused by contact of the base material at a stripping position and air is effectively reduced; 4. the conventional wire filling welding can generate welding seam surplus height, and the surplus height is too high, so that the subsequent hot forming process is not favorable, and a die is abraded; the substrate groove method provided by the invention can effectively reduce the excess height and ensure that the excess height meets the requirement of thermal forming. The method of the invention not only ensures that the plating metal can not enter the molten pool, but also ensures that the filling metal can cover the stripping part to the maximum extent, and can effectively prevent the plating metal at the edge part from melting into the molten pool along with the welding thermal cycle; in addition, the welding quality is ensured, and meanwhile, the method has the characteristics that the technological process is easy to implement, the method is suitable for large-scale production and manufacturing, and the stability of batch production can be ensured.

Drawings

The invention will be further explained with reference to the drawings.

FIG. 1 is a schematic view of a substrate groove on the surface of a plated hot formed steel sheet material to be welded;

FIG. 2 is a schematic view of a weld of a plated hot formed steel sheet.

The reference numbers in the figures are: 1. alloy-layer, 2, transition layer, 3, substrate, 4, substrate recess, 5, welding seam.

Detailed Description

The technical core of the invention is that the surface layer, the transition layer and part of the base material of the part to be welded of the aluminum or aluminum alloy coating hot forming steel are removed by laser or other high-energy beams (plasma arc, water jet and the like) to form a base material groove. In order to ensure the uniformity of groove forming, the input energy ratio of the laser or high-energy beam in the region covered by the removal width of the middle part 2/3 of the groove and the region covered by the removal width of the edge part 1/3 needs to be more than 100%, otherwise, in the process of removing the coating and the substrate, energy can be gathered at the edge part, so that the uniformity of groove forming is affected, and the problem of stress concentration is caused. Then, the hot formed plate is welded by laser filler wire welding, and the method of the invention is described in detail below with reference to the accompanying drawings.

Referring to fig. 1 and 2, the method of the present invention comprises the following steps:

a. and (3) completely removing the alloy layer 1 and the transition layer 2 at the part to be welded of the aluminum or aluminum alloy coating hot-formed steel plate material, and simultaneously removing part of the base material 3 to form a base material groove 4. The removal method is preferably laser, and plasma arc or water jet may be used. The shape of the substrate groove can be rectangular or curved. The laser can be removed vertically to the surface of the coating and the substrate or at a certain angle to the surface of the coating and the substrate, and the laser sweeping mode is a sine wave mode (or other sweeping modes meeting the energy distribution requirement). The substrate removal process is carried out on at least one side of the site to be welded. The substrate groove depth and width dimensions are dependent on the removal method employed, typically the substrate groove depth H is from 2 μm to 100 μm, preferably from 10 μm to 50 μm; the width W of the substrate groove is 0.5 to 3mm, preferably 1 to 1.5 mm.

b. And selecting the welding wires according to the components of the base material and the depth of the groove of the base material. The components of the welding wire are consistent or close to those of the base material so as to ensure the quality of the welding seam and facilitate the consistency of the mechanical properties of the base material and the welding seam after heat treatment. The welding wire comprises C, Si, Mn, S, P and Fe, wherein the percentage content of the C, Si and Mn elements is 0.8-1.2 times of the percentage content of the C, Si and Mn elements in the base material; the percentage content of the P and S elements in the welding wire composition does not exceed the percentage content of the P and S elements in the base material composition. When the depth of the groove of the base material is more than 30 μm, 0.002-0.012% of B element is added into the welding wire composition in consideration of the hardenability of the welding seam. The welding wire can also add 0.01-0.1% of Cr and 0.01-0.1% of Ni according to the components of the base material.

c. And welding the hot-formed plate by using a laser wire filling welding mode. The welding process adopts the measure of reducing the surface tension of the molten metal, for example, the mixed protective gas of oxygen and argon is adopted, so that the molten metal is uniformly spread in the groove of the base material, and the contact range of the base material at the stripping part and air is reduced to the maximum extent. The cross-sectional area of the welding line is decreased gradually from the base material removing surface to two sides, the molten metal is spread to two sides of the base material groove to the maximum extent, the surface of the base material is covered, and the contact range of the base material at the stripping part and air is effectively reduced.

d. And (3) keeping the temperature of the welded product piece at 930-950 ℃ for 300s, and quenching at a cooling speed of more than 30 DEG/s.

One specific example is provided below:

the aluminum alloy coating hot-formed steel of 22MnB5 comprises the following components in percentage by weight: less than or equal to 0.22 percent of C, less than or equal to 0.28 percent of Si, 1.25-1.3 percent of Mn1, 0.12-0.13 percent of Cr, 0.0022-0.0025 percent of B, 0.38 percent of Als, less than or equal to 0.011 percent of P, less than or equal to 0.0022 percent of S, 0.03-0.02 percent of Ti and the balance of Fe.

The welding wire comprises the following components in percentage by weight: 0.20 percent of C, 0.30 percent of Si, 1.45 percent of Mn, 0.03 percent of Cr, 0.02 percent of Ni0.010 percent of P and 0.009 percent of S.

Removing the aluminum-silicon plating layer and part of the base material of the 22MnB5 by adopting nanosecond laser, wherein the removing depth of the base material is 20-30 mu m, the average power of the nanosecond laser is 300W, the advancing speed is 2m/min, the irradiation is carried out vertical to the surface of the workpiece, and the input energy ratio of the laser in the area covered by the removing width of the middle part 2/3 and the area covered by the removing width of the edge part 1/3 of the groove of the base material is more than 100%; performing laser wire filling welding on the removed part, wherein the laser power is 4kW, and the welding speed is 5 m/min; and heating the sample to 950 ℃ in a furnace after welding, preserving heat for 300s, and then quenching. And (3) performing a tensile test on the quenching test plate according to the national standard, wherein the joint is broken at the base metal, and the welding joint performance is not lower than that of the base metal. The mechanical properties of the tailor welded joint were measured as follows: