阅读说明：本技术 一种激光制造与再制造电厂最小流量阀阀芯的合金材料及其制备方法 (Alloy material for laser manufacturing and remanufacturing of minimum flow valve core of power plant and preparation method thereof ) 是由 倪春雷 陈海涛 董思远 于 2021-08-18 设计创作，主要内容包括：本发明属于金属材料和激光熔覆技术领域,具体涉及一种激光制造与再制造阀门用合金材料及其制备方法。一种激光制造与再制造电厂最小流量阀阀芯的合金材料,由以下质量百分数的组分组成：C：0.40%～0.95%,Cr：19.00%～23.75%,Si：1.40%～1.90%,W：6.65%～9.50%,Fe：2.00%～3.00%,Mo：0.50%～1.00%,Ni：8.00%～12.00%,Al：0.20%～1.00%,B：0.50%～2.50%,Co余量。本发明提供一种最小流量阀阀芯用耐腐蚀抗冲蚀高性能材料,所用合金材料为钴基合金,实现最小流量循环阀核心组件之一阀芯的使用寿命,解决阀芯不耐冲蚀易内泄的问题。(The invention belongs to the technical field of metal materials and laser cladding, and particularly relates to an alloy material for a valve manufactured and remanufactured by laser and a preparation method thereof. The alloy material for laser manufacturing and remanufacturing the valve core of the minimum flow valve of a power plant comprises the following components in percentage by mass: c: 0.40% -0.95%, Cr: 19.00% -23.75%, Si: 1.40% -1.90%, W: 6.65% -9.50%, Fe: 2.00-3.00%, Mo: 0.50% -1.00%, Ni: 8.00-12.00%, Al: 0.20% -1.00%, B: 0.50% -2.50% and the balance of Co. The invention provides a corrosion-resistant erosion-resistant high-performance material for a minimum flow valve core, which is a cobalt-based alloy, so that the service life of one valve core of a minimum flow circulating valve core assembly is prolonged, and the problem that the valve core is not erosion-resistant and is easy to leak is solved.)

1. The alloy material for laser manufacturing and remanufacturing the valve core of the minimum flow valve of a power plant is characterized by comprising the following components in percentage by mass: c: 0.40% -0.95%, Cr: 19.00% -23.75%, Si: 1.40% -1.90%, W: 6.65% -9.50%, Fe: 2.00-3.00%, Mo: 0.50% -1.00%, Ni: 8.00-12.00%, Al: 0.20% -1.00%, B: 0.50% -2.50% and the balance of Co.

2. The preparation method of the alloy material for manufacturing and remanufacturing the valve core of the minimum flow valve of the power plant by laser is characterized by comprising the following steps of:

step 1, preparing functional layer powder: c: 0.40% -0.95%, Cr: 19.00% -23.75%, Si: 1.40% -1.90%, W: 6.65% -9.50%, Fe: 2.00-3.00%, Mo: 0.50% -1.00%, Ni: 8.00-12.00%, Al: 0.20% -1.00%, B: 0.50-2.50% of Co, and the balance of Co in mass fraction to prepare functional layer powder;

step 2, laser cladding: presetting a layer of alloy layer with the thickness of 1.2-2.0 mm on the surface of the valve core in a powder feeding mode, and selecting an optical fiber output laser with the highest laser output power of 3000-4000W for scanning cladding;

step 3, surface processing: and processing the surface of the functional layer after cladding is finished, and keeping the thickness of the laser cladding layer to be 0.7-1.5 mm.

3. The method for preparing the alloy material for the valve core of the minimum flow valve of the power plant through laser manufacturing and remanufacturing according to claim 2, wherein the cladding process in the step 2 is as follows: power density 143W/mm²~353W/mm²The scanning speed: 700-1500 mm/min, lap joint rate: 40% -60%, protective atmosphere: controlling the oxygen content around the molten pool and the valve core to be less than 1000ppm in the cladding process by argon.

Technical Field

The invention belongs to the technical field of metal materials and laser cladding, and particularly relates to an alloy material for a valve manufactured and remanufactured by laser and a preparation method thereof.

Background

The boiler system is used as the core of a thermal power plant, and whether the boiler system can safely operate or not is particularly important. The minimum flow circulating valve is used as an important flow control component in a boiler water supply system, and the performance of the minimum flow circulating valve directly influences the normal operation of the whole unit.

The minimum flow circulating valve is arranged between the feed pump and the deaerator and is one of the worst regulating valves in the thermal power plant. In order to prevent the feed water pump from overheating and generating cavitation damage, the flow rate of the feed water pump must not be less than a certain specified safety flow rate, i.e., a minimum flow rate, in any case. When the required flow of boiler feed water is smaller than the minimum flow of the feed pump, the minimum flow circulating valve needs to be opened in time, and a part of high-temperature and high-pressure water flows back to the deaerator from the outlet of the pump, so that the safe operation of the feed pump is ensured. And the minimum flow circulation valve is in a high-temperature and high-pressure working environment for a long time, the strong pressure fluctuation of a medium, high-flow-rate scouring and the opening and closing of the valve can cause the failure of the sealing surface of the valve core of the core component of the valve, so that the working surface of the valve core is not tightly sealed with the valve seat, leakage occurs, and the operation safety of the whole boiler system can be threatened in severe cases. The cobalt-based alloy is mostly welded on the working surface in the manufacturing of the conventional valve core, but because the heat input of welding is large, the component difference of the welded cobalt-based working surface is large, and the service life of the welded cobalt-based working surface is often not expected in the using process.

Disclosure of Invention

In view of the problems in the prior art, the invention aims to provide an alloy material for laser manufacturing and remanufacturing a minimum flow valve core, and the alloy material is prepared on a working surface of the valve core by a laser cladding method. The invention provides a corrosion-resistant erosion-resistant high-performance material for a minimum flow valve core, which is a cobalt-based alloy, so that the service life of one valve core of a minimum flow circulating valve core assembly is prolonged, and the problem that the valve core is not erosion-resistant and is easy to leak is solved.

In order to achieve the purpose, the invention adopts the following technical scheme.

The alloy material for laser manufacturing and remanufacturing the valve core of the minimum flow valve of a power plant comprises the following components in percentage by mass: c: 0.40% -0.95%, Cr: 19.00% -23.75%, Si: 1.40% -1.90%, W: 6.65% -9.50%, Fe: 2.00-3.00%, Mo: 0.50% -1.00%, Ni: 8.00-12.00%, Al: 0.20% -1.00%, B: 0.50% -2.50% and the balance of Co.

A preparation method of an alloy material for laser manufacturing and remanufacturing a valve core of a minimum flow valve of a power plant comprises the following specific steps:

step 1, preparing functional layer powder: c: 0.40% -0.95%, Cr: 19.00% -23.75%, Si: 1.40% -1.90%, W: 6.65% -9.50%, Fe: 2.00-3.00%, Mo: 0.50% -1.00%, Ni: 8.00-12.00%, Al: 0.20% -1.00%, B: 0.50% -2.50%, and functional layer powder is prepared according to the mass fraction of the balance of Co.

Step 2, laser cladding: a powder feeding mode is adopted to preset a layer of alloy layer with the thickness of 1.2-2.0 mm on the surface of the valve core, and an optical fiber output laser with the highest laser output power of 3000-4000W is selected for scanning cladding.

Step 3, surface processing: and processing the surface of the functional layer after cladding is finished, and keeping the thickness of the laser cladding layer to be 0.7-1.5 mm.

Further, the cladding process in the step 2 comprises the following steps: power density 143W/mm²~353W/mm²The scanning speed: 700-1500 mm/min, lap joint rate: 40% -60%, protective atmosphere: controlling the oxygen content around the molten pool and the valve core to be less than 1000ppm in the cladding process by argon.

Compared with the prior art, the invention has the following beneficial effects.

(1) The invention adopts a lower laser cladding process, so that the dilution rate of the clad alloy layer is controlled to be less than 10 percent, thereby ensuring the use effect of the cladding layer.

(2) According to the alloy material for the laser manufacturing and remanufacturing valve, a certain amount of Al element is added, so that the O content in the protective atmosphere in the cladding process can be reduced, the oxygen content in the cladding layer can be reduced, the problem that cobalt-based alloy cladding is prone to generate pores can be solved, and Al is formed at the same time₂O₃Can be used as heterogeneous nucleating agent in the cladding layer to refine grains, improve the toughness of the cladding layer and improve the wear resistance of the cladding layer. And the carbide in the cobalt-based alloy acts together, so that the erosion resistance and the wear resistance of the cladding layer are improved.

(3) According to the alloy material for the laser manufacturing and remanufacturing valve, due to the fact that a proportion of Ni element is added, the plasticity is further improved, the content of B in an alloy layer is properly increased, the content of boride in a cladding layer is improved, and the erosion resistance is improved; properly increasing the content of Si and improving the oxidation resistance of the cladding layer at 180 ℃. However, the brittleness of the cladding layer is increased due to excessive B and Si contents, the laser rapid cold cladding is not facilitated, and meanwhile, in use, the sealing surface is stripped in a point shape due to the switch impact of a valve and the cavitation of water, so that the sealing surface is failed.

Detailed Description

The following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

The alloy material for laser manufacturing and remanufacturing the valve core of the minimum flow valve of a power plant comprises the following components in percentage by mass: c: 0.40% -0.95%, Cr: 19.00% -23.75%, Si: 1.40% -1.90%, W: 6.65% -9.50%, Fe: 2.00-3.00%, Mo: 0.50% -1.00%, Ni: 8.00-12.00%, Al: 0.20% -1.00%, B: 0.50% -2.50% and the balance of Co.

A preparation method of an alloy material for laser manufacturing and remanufacturing a valve core of a minimum flow valve of a power plant comprises the following specific steps:

step 1, preparing functional layer powder: c: 0.40% -0.95%, Cr: 19.00% -23.75%, Si: 1.40% -1.90%, W: 6.65% -9.50%, Fe: 2.00-3.00%, Mo: 0.50% -1.00%, Ni: 8.00-12.00%, Al: 0.20% -1.00%, B: 0.50% -2.50%, and functional layer powder is prepared according to the mass fraction of the balance of Co.

Step 2, laser cladding: a powder feeding mode is adopted to preset a layer of alloy layer with the thickness of 1.2-2.0 mm on the surface of the valve core, and an optical fiber output laser with the highest laser output power of 3000-4000W is selected for scanning cladding.

Step 3, surface processing: and processing the surface of the functional layer after cladding is finished, and keeping the thickness of the laser cladding layer to be 0.7-1.5 mm.

Further, the cladding process in the step 2 comprises the following steps: power density 143W/mm²~353W/mm²The scanning speed: 700-1500 mm/min, takeThe grafting ratio: 40% -60%, protective atmosphere: controlling the oxygen content around the molten pool and the valve core to be less than 1000ppm in the cladding process by argon.

Example 1.

1. Removing oil stains, oxides, fatigue layers and other factors which influence the cladding quality on the surface to be clad.

2. A powder feeding mode is adopted to preset a layer of alloy layer with the thickness of 1.2mm on the working surface of the valve core, and the components are as follows: c: 0.40%, Cr: 19.00%, Si: 1.40%, W: 6.65%, Fe: 2.00%, Mo: 0.50%, Ni: 8.00%%, Al: 0.20%, B: 0.50% and the balance of Co.

3. A3000W fiber laser is selected for scanning cladding, and the cladding process comprises the following steps: power density 180W/mm²The scanning speed: 700mm/min, lap joint rate: 60%, protective atmosphere: controlling the oxygen content around the molten pool and the valve core to be 800ppm in the cladding process by argon.

4. The cladding layer was processed to a thickness of 1.0 mm.

Example 2.

1. Removing oil stains, oxides, fatigue layers and other factors which influence the cladding quality on the surface to be clad.

2. A powder feeding mode is adopted to preset a layer of alloy layer with the thickness of 1.7mm on the working surface of the valve core, and the components are as follows: c: 0.50%, Cr: 20.20%, Si: 1.50%, W: 7.50%, Fe: 2.50%, Mo: 0.70%, Ni: 9.50%, Al: 0.70%, B: 1.50 percent and the balance of Co.

3. A3000W fiber laser is selected for scanning cladding, and the cladding process comprises the following steps: power density 220W/mm²The scanning speed: 800mm/min, lap joint rate: 50%, protective atmosphere: argon gas, and the oxygen content around the molten pool and the valve core is controlled to be 600ppm in the cladding process.

4. The cladding layer was processed to a thickness of 1.2 mm.

Example 3.

1. Removing oil stains, oxides, fatigue layers and other factors which influence the cladding quality on the surface to be clad.

2. A2.0 mm thick alloy layer is preset on the working surface of the valve core in a powder feeding mode, and the alloy layer comprises the following components: 0.95%, Cr: 23.75%, Si: 1.90%, W: 9.50%, Fe: 3.00%, Mo: 1.00%, Ni: 12.00%, Al: 1.00%, B: 2.50 percent and the balance of Co.

3. A3000W fiber laser is selected for scanning cladding, and the cladding process comprises the following steps: power density: 350W/mm²The scanning speed: 1500mm/min, lap joint rate: 50%, protective atmosphere: argon gas, and the oxygen content around the molten pool and the valve core is controlled to be 100ppm in the cladding process.

4. The cladding layer was processed to a thickness of 1.5 mm.

The alloy material prepared by the invention is cladded on the working surface of the valve core through the embodiment, the surface hardness can reach more than 45HRC, and the surface has no crack and pore defects after processing. The longest on-line service time of the valve core can reach 3 years, and the service life of the valve core is prolonged by at least 3 times compared with that of the original valve core.