CN-121992304-A - Laser cladding process method for improving hardness wear resistance and metallurgical bonding strength based on S element

Abstract

The invention discloses a laser cladding process method for improving hardness and wear resistance and metallurgical bonding strength based on an S element, and belongs to the technical field of metal material surface modification. In the laser cladding process, the S-element-containing powder is added into the mixed powder, so that the flow mode of a molten pool is fundamentally changed, the phenomenon of 'molten pool downward' is generated by the Marangoni effect, the phenomenon increases the fusion depth of the molten pool, the bonding area of a cladding layer and a matrix is increased, the metallurgical bonding strength is enhanced, grains in the molten pool are thinned due to strong convection in the molten pool, fine hard phases are formed, the wear resistance and the hardness of the cladding layer are enhanced, the service life of the cladding layer is prolonged, and the method is suitable for the fields of industrial part remanufacturing and surface strengthening with extremely high requirements on the wear resistance, the impact resistance and the coating bonding strength.

Inventors

• SUN YICHANG
• LIU XU
• FENG LEI
• SHANG HANG
• WEI PENGFEI
• Chen Menjia
• XU PENGFEI
• LI MIAO
• LIU XINYUE

Assignees

• 大连工业大学艺术与信息工程学院

Dates

Publication Date

20260508

Application Date

20260306

Claims (8)

1. 1. A laser cladding process method for improving hardness wear resistance and metallurgical bonding strength based on S element is characterized by comprising the following steps: 1) Carrying out jet milling treatment on the Fe-based autolytic alloy powder and the S powder, and drying to obtain Fe-based S powder, wherein the Fe-based autolytic alloy powder is more than or equal to 99.9wt% and the S powder is less than or equal to 0.1wt%; polishing the surface of the substrate and then cleaning; 2) The cleaned matrix is sent into a heating furnace and preheated for 3 to 5 hours at the temperature of 300 to 400 ℃; 3) After the furnace is opened, the Fe-based S powder is clad on the surface of the substrate by adopting a laser cladding method, and the Fe-based S powder alloy composite coating is formed on the surface of the substrate.
2. 2. The laser cladding process method for improving hardness and wear resistance and metallurgical bonding strength based on S element as claimed in claim 1, wherein in the step 1), the Fe-based self-soluble alloy powder consists of the following components in percentage by mass: 6.9 to 7.1 percent of Ni, 22.95 to 23.05 percent of Cr, 2.97 to 3.03 percent of Si, 2.96 to 3.04 percent of B, 3.97 to 4.04 percent of C and the balance of F e.
3. 3. The laser cladding process method for improving hardness and wear resistance and metallurgical bonding strength based on S element according to claim 1, wherein in the step 1), the particle size of S powder before air flow grinding treatment is 150-300 μm.
4. 4. The laser cladding process method for improving hardness and wear resistance and metallurgical bonding strength based on S element according to claim 1, wherein in the step 1), the air flow mill sucks Fe-based self-soluble alloy powder and S powder into an air flow pulverizer through air flow, powder particles are accelerated by the air flow and collide with each other vigorously in a pulverizing cavity to realize uniform mixing of powder components and fine particle size, and the particle size of the S powder after the air flow milling treatment is 50-100 μm.
5. 5. The laser cladding process method for improving hardness and wear resistance and metallurgical bonding strength based on S element according to claim 4, wherein the air flow pressure is 0.7MPa-1.2 MPa, and the powder particles are accelerated to 150m/S-300m/S by the air flow.
6. 6. The laser cladding process method for improving hardness and wear resistance and metallurgical bonding strength based on S element as claimed in claim 1, wherein in the step 1), a grinding machine is used for grinding the surface of a substrate together with 320# 600 abrasive paper, and acetone is used for cleaning.
7. 7. The laser cladding process method for improving hardness and wear resistance and metallurgical bonding strength based on the S element as claimed in claim 1, wherein in the step 3), the process parameters of laser cladding are that the laser power is 1500W-3000W, the scanning speed is 5-12mm/S, the spot diameter is 2-4mm, the powder feeding rate is 15-30g/min, the lap joint rate is 40-60%, and the distance between a laser cladding head and a substrate is 15-30mm.
8. 8. The laser cladding process method for improving hardness and wear resistance and metallurgical bonding strength based on S element according to claim 1, wherein in the step 3), the thickness of the Fe-based S powder alloy composite coating is 0.5-2.0mm.

Description

Laser cladding process method for improving hardness wear resistance and metallurgical bonding strength based on S element Technical Field The invention belongs to the technical field of metal material surface modification, and particularly relates to a laser cladding process method for improving hardness wear resistance and metallurgical bonding strength based on an S element. Background The laser cladding technology is used as a key technology in the fields of remanufacturing engineering and surface strengthening, and the wear resistance, corrosion resistance and service life of mechanical parts can be remarkably improved by preparing the high-performance alloy coating on the surface of the substrate. Among them, iron-based alloy powders, particularly the Fe series, are widely used in industrial wear-resistant part repair and reinforcement due to their excellent cost effectiveness and good compatibility with steel substrates. However, existing Fe-based laser cladding techniques still face two major core challenges. First, the coating has insufficient comprehensive wear-resistant antifriction performance. The traditional Fe coating mainly improves the hardness and the wear resistance through carbide and boride hard phases generated in situ, but the method often leads to the increased brittleness of the coating and is difficult to achieve antifriction performance. Under high load or poor lubrication friction conditions, the coating is susceptible to early failure due to high coefficient of friction and consequent adhesive wear and frictional heat. Second, the metallurgical bond strength between the coating and the substrate is to be further improved. The rapid non-equilibrium nature of the laser cladding process makes the lifetime of the melt pool extremely short, and the wettability of the Fe alloy melt to the substrate becomes critical in determining the quality of the bond. Poor wettability is likely to cause defects such as unfused and air holes at the interface, and becomes a crack source for peeling off the coating under complex stress. Although preheating processes are commonly employed in the industry to reduce thermal stresses, the wetting and spreading behavior of the puddle is not fundamentally improved. To solve the above problems, researchers have attempted to add various types of modifying elements to the cladding powder. Sulfur (S) is used as a strong surface active element, the wettability can be improved theoretically by obviously reducing the surface tension of a molten pool, so that the metallurgical bonding is enhanced, meanwhile, S can also form a sulfide self-lubricating phase in a coating, the friction coefficient is hopefully reduced, and the synergy of wear resistance and antifriction is realized. However, in conventional metallurgical concepts, S is often regarded as a detrimental impurity, the introduction of which causes hot shortness and significantly increases crack sensitivity, resulting in the prior art having long been widespread in avoiding the active addition of S element in laser cladding. How to precisely control the addition amount and the distribution manner of the S so as to fully utilize the positive effects of improving wettability and providing lubrication, and effectively inhibit the crack risk caused by the S, has become a technical bottleneck to be broken through in the field. The patent publication No. CN120796970A discloses a preparation method and a process for a laser cladding cobalt-based wear-resistant coating on the surface of a titanium alloy, which provides the laser cladding cobalt-based wear-resistant coating on the surface of the titanium alloy, and takes titanium or the titanium alloy as a base material, and comprises, by weight, 40-50% of cobalt (Co), 30-40% of tungsten carbide (WC), 10-15% of chromium (Cr), 1-5% of lanthanum hexaboride (LaB 6), 2-5% of silicon (Si), 0.5-3% of calcium fluoride (CaF 2), and the like, and is used for improving the wear resistance, high-temperature stability, corrosion resistance, high hardness, high bonding strength, difficulty in cracking and the like of the coating. However, the bonding interface between the coating and the matrix is not compact, has more defects and has poor spreadability. The patent publication No. CN119824409A discloses a preparation method of a tin-based Babbitt metal laser cladding coating added with Ti element, which is used for obtaining a tin-based Babbitt metal coating containing Ti. The method comprises the steps of adding a certain proportion of metal Ti powder into tin-based Babbitt alloy powder, adding the obtained metal Ti powder and the tin-based Babbitt alloy powder into a mixer, and mixing for 5-6 hours to obtain composite powder. And cladding the mixed powder of the tin-based Babbitt alloy and the Ti powder on the surface of the 20 steel by using a coaxial powder feeding laser cladding mode to obtain the tin-based Babbitt alloy coating added with the Ti element. Although good meta