Stainless steel solid wire for surfacing welding and its preparation method

Abstract

The present invention relates to a stainless steel solid wire for surfacing and a preparation method thereof. The chemical composition of the stainless steel solid wire is as follows by mass percentage: C ≤ 0.03 wt%; Mn: 1.8 - 3.5 wt%; Si: 0.6 - 1.2 wt%; Cr: 19.5 - 22 wt%; Ni: 12.5 - 14.5 wt%; P ≤ 0.03 wt%; S ≤ 0.01 wt%; Mo: 2.7 - 3.5 wt%; Cu ≤ 0.2 wt%, and the balance is Fe and inevitable impurities. The present invention improves the stability of surfacing of the deposited metal performance of the wire. Since the wire has made a great change on the basis of the national standard E316L composition, the difficulty of the wire smelting and manufacturing process is increased.

Description

Technical Field

[0001] The present invention relates to solid cored wires, and particularly to stainless steel solid cored wires for surfacing and their preparation methods. Background Art

[0002] As an economical and rapid process method for material surface modification, surfacing is increasingly widely used in the manufacturing and repair of parts in various industrial sectors. In order to most effectively play the role of the surfacing layer, it is hoped that the surfacing method adopted has less dilution of the base material, higher deposition rate and excellent surfacing layer properties, that is, a high-quality, high-efficiency and low-dilution rate surfacing technology.

[0003] The wire often used in surfacing is the national standard E316L, and its components are C≤0.03wt%; Mn: 1-2.5wt%; Si: 0.3-0.65wt%; Cr: 18-20wt%; Mo: 2.0-7-3.0wt%; P≤0.03wt%; S≤0.03wt%; Cu≤0.75wt%, and the balance is Fe and inevitable impurities. In the existing surface surfacing, in order to ensure the surfacing quality, it is often necessary to use E316L wire for multi-layer surfacing, and single-pass surfacing cannot be achieved. At the same time, the ferrite content of the deposited metal of E316L wire is low, and it is easy to form chromium-depleted grain boundaries, and the intergranular corrosion resistance is poor.

[0004] Since a slight adjustment of the components of stainless steel solid cored wires often results in essential differences in products, the research and development of stainless steel solid cored wires is difficult. Summary of the Invention

[0005] The first object of the present invention is to provide a stainless steel solid cored wire for surfacing, and the stainless steel solid cored wire has made great changes on the basis of the national standard E316L composition, increasing the difficulty of the wire smelting and manufacturing process.

[0006] The technical solution for achieving the first object of the present invention is: the chemical composition mass percentage of the stainless steel solid cored wire in the present invention is: C≤0.03wt%; Mn: 1.8-3.5wt%; Si: 0.6-1.2wt%; Cr: 19.5-22wt%; Ni: 12.5-14.5wt%; P≤0.03wt%; S≤0.01wt%; Mo: 2.7-3.5wt%; Cu≤0.2wt%, and the balance is Fe and inevitable impurities. The tensile strength of the stainless steel solid cored wire prepared by this formula is ≥560 Mpa, and the elongation is ≥25%.

[0007] As a preferred design, the chemical composition of the stainless steel solid wire by mass percentage is: C: 0.021 wt%; Mn: 2.87 wt%; Si: 0.9 wt%; Cr: 20.87 wt%; Ni: 12.87 wt%; P: 0.018 wt%; S: 0.005 wt%; Mo: 2.85 wt%; Cu: 0.09 wt%, and the balance is Fe and unavoidable impurities.

[0008] The second object of the present invention is to provide a preparation method for the above-mentioned stainless steel solid wire. According to the formulation characteristics of the preparation method, a stainless steel solid wire with better morphology and better welding effect can be prepared.

[0009] The technical solution for achieving the second object of the present invention is: The preparation method in the present invention includes the following steps:

[0010] S1. Prepare each chemical component according to the formulation;

[0011] S2. Smelt the chemical components in step S1, cast them into ingots and then roll them into wire rods;

[0012] S3. The rolled wire rods are subjected to normalizing and high-temperature tempering heat treatment, and then drawn. During the drawing process, 1-3 times of annealing heat treatment are carried out, and finally drawn into wires.

[0013] The specific steps of the normalizing and high-temperature tempering heat treatment in step S3 above are: First, normalize at a temperature of 1150 - 1180 °C and hold for 2 - 3 hours; then carry out high-temperature tempering at a temperature of 720 - 760 °C and hold for 1.5 - 2 hours.

[0014] The annealing heat treatment in step S3 is carried out at 1080 - 1120 °C for 90 - 180 seconds.

[0015] In step S2, the diameter of the wire rod is φ5.5 mm. In step S3, the diameter of the wire is φ0.8 - φ1.2 mm.

[0016] The present invention has positive effects: (1) The present invention improves the stability of the surfacing of the deposited metal performance of the wire. Since the wire has made great changes on the basis of the national standard E316L composition, it increases the difficulty of the wire smelting and manufacturing process.

[0017] (2) The present invention controls the contents of Cr, Mn, Si, and Mo within a corresponding range. Among them, increasing the Si content is beneficial to the fluidity of molten steel during welding, and it is easier to control the width and height of the weld bead. At the same time, since the weld bead is flatter, the cutting ratio of the weld bead surface is reduced. Therefore, compared with the conventional E316 solid wire, during surfacing, only one layer of surfacing is required with the stainless steel solid wire of the present invention, and no multi-layer surfacing on the surface is needed, reducing the machining amount on the surface after surfacing, that is, improving work efficiency, reducing the surface cutting rate, and saving material costs.

[0018] (3) The increase in the Mn content in the present invention reduces the phenomenon of hot cracks on the surfacing surface, improves the surface machining quality and the first-pass yield. Since the phenomenon of micro-cracks is reduced, the corrosion resistance of the surfacing surface is greatly improved, and the first-pass yield of the surface machining quality is improved.

[0019] (4) The significant increase in Cr, Ni, and Mo in the present invention ensures the primary dilution rate of the components, ensuring the corrosion resistance to acetic acid, sulfurous acid, phosphoric acid, and salts.

[0020] (5) Due to the significant increase in the contents of Cr and Mo, with a large increase in Cr, the steel ingot is prone to cracking and splitting during the rolling process, and the finished product rate of the wire rod is low. Through continuous exploration, it is found that reducing the rolling temperature of the wire rod and adjusting the Mn content in the components can solve the above problems. Therefore, the setting of process parameters in the preparation method of the present invention can effectively solve the above problems, and it is also a process design in coordination with its components. Specific Embodiments

[0021] (Example 1)

[0022] For the stainless steel solid wire used for surface surfacing in the present invention, the mass percentages of its chemical components are as follows: C: 0.021 wt%; Mn: 2.87 wt%; Si: 0.9 wt%; Cr: 20.87 wt%; Ni: 12.87 wt%; P: 0.018 wt%; S: 0.005 wt%; Mo: 2.85 wt%; Cu: 0.09 wt%, and the balance is Fe and inevitable impurities.

[0023] The preparation method for preparing the above stainless steel solid wire includes the following steps:

[0024] S1. Prepare each chemical component according to the formula;

[0025] S2. Smelt each chemical component in step S1, cast it into an ingot blank, and then roll it into a wire rod;

[0026] S3. Perform normalizing and high-temperature tempering heat treatment on the rolled wire rod, then perform drawing, and perform 1 - 3 times of annealing heat treatment during the drawing process, and finally draw it into a wire.

[0027] The specific steps of normalizing and high-temperature tempering heat treatment in step S3 are as follows: First, normalize at a temperature of 1150 - 1180 °C for 2 - 3 hours; then perform high-temperature tempering at a temperature of 720 - 760 °C for 1.5 - 2 hours.

[0028] The annealing heat treatment in step S3 is carried out at 1080 - 1120 °C for 90 - 180 seconds.

[0029] (Example 2)

[0030] For the solid stainless steel wire used for surface surfacing in the present invention, the chemical composition by mass percentage is: C: 0.023 wt%; Mn: 1.95 wt%; Si: 0.75 wt%; Cr: 19.87 wt%; Ni: 12.87 wt%; P: 0.019 wt%; S: 0.005 wt%; Mo: 2.85 wt%; Cu: 0.097 wt%, and the balance is Fe and unavoidable impurities.

[0031] (Comparative Example)

[0032] A comparative test was carried out using E316L stainless steel wire. The chemical composition by mass percentage of the E316L solid wire is: C: 0.021 wt%; Mn: 1.50 wt%; Si: 0.45 wt%; Cr: 18.32 wt%; Ni: 11.13 wt%; P: 0.023 wt%; S: 0.007 wt%; Mo: 2.21 wt%; Cu: 0.089 wt%, and the balance is Fe and unavoidable impurities.

[0033] Surfacing was carried out on the same E304L valve body substrate using the same welding process and the same gas: pure Ar (≥99.9%). After surfacing one layer by gas shielded welding, the chemical composition of the surface surfacing layer measured by spectroscopy is as follows:

[0034] Example 2: Mn: 1.63 wt%; Cr: 19.41 wt%; Ni: 11.74 wt%; Mo: 2.47 wt%;

[0035] Comparative Example: Mn: 1.30 wt%; Cr: 18.29 wt%; Ni: 10.30 wt%; Mo: 1.92 wt%;

[0036] From the comparison of the above data, it can be seen that after surfacing one layer in Example 2, the chemical composition meets the requirements of the conventional E316L chemical composition, and there are no crack phenomena on the surface.

[0037] In the comparative example, Ni and Mo still do not meet the requirements of the conventional E316L standard, and the Cr content is low.

[0038] A layer of surfacing was deposited on the surfacing layer of the comparative example, and the chemical composition of the second layer of surfacing was measured as follows:

[0039] Mn: 1.43 wt%; Cr: 18.31 wt%; Ni: 10.91 wt%; Mo: 2.10 wt%;

[0040] It can be seen from this that even if two layers of surfacing are deposited, the Ni content is still low. When purchasing, it is necessary to require the other party's welding wire to have a higher Ni content to ensure that the composition of the surfacing layer meets the requirements.

[0041] The specific embodiments described above have further elaborated on the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A stainless steel solid wire for surfacing, characterized in that: The chemical composition of the stainless steel solid wire in mass percentage is as follows: C: 0.021 wt%; Mn: 2.87 wt%; Si: 0.9 wt%; Cr: 20.87 wt%; Ni: 12.87 wt%; P: 0.018 wt%; S: 0.005 wt%; Mo: 2.85 wt%; Cu: 0.09 wt%, and the balance is Fe and inevitable impurities.

2. The preparation method of the stainless steel solid cored wire for surfacing welding as described in claim 1, characterized in that It includes the following steps: S1. Prepare each chemical component according to the formula; S2. Smelt the chemical components in step S1, cast them into ingots and then roll them into wire rods; S3. The rolled wire rods are subjected to normalizing and high-temperature tempering heat treatment, and then drawn. During the drawing process, 1 - 3 times of annealing heat treatment are carried out, and finally drawn into wires.

3. The preparation method according to claim 2, characterized in that: The specific steps of the normalizing and high-temperature tempering heat treatment in step S3 are as follows: first normalize at a temperature of 1150 - 1180 °C and hold for 2 - 3 hours; then carry out high-temperature tempering at a temperature of 720 - 760 °C and hold for 1.5 - 2 hours.

4. The preparation method according to claim 3, characterized in that: The annealing heat treatment in step S3 is carried out at 1080 - 1120 °C for 90 - 180 seconds.