Alloy powder for repairing martensitic steel by laser additive manufacturing and its preparation and application

A technology of alloy powder and laser additive materials, which is applied in the direction of additive manufacturing, additive processing, and improvement of process efficiency. Cycle, the effect of expanding the scope of application

Active Publication Date: 2021-05-18
HUAZHONG UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In view of the above defects or improvement needs of the prior art, the present invention provides an alloy powder for repairing martensitic steel by laser additive manufacturing and its preparation and application, which can be adjusted by adjusting C, Cr, Ni, Mn, Si, etc. The proportion of alloying elements, reducing the Ms point, using the volume expansion accompanied by the martensitic transformation to offset the tensile stress formed during the solidification process, and obtain the compressive stress in the repaired area, thus solving the problem that the existing technology of additive manufacturing repairing martensitic steel cannot obtain Technical problems of compressive stress in the repaired area and poor repairing effect

Method used

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  • Alloy powder for repairing martensitic steel by laser additive manufacturing and its preparation and application
  • Alloy powder for repairing martensitic steel by laser additive manufacturing and its preparation and application
  • Alloy powder for repairing martensitic steel by laser additive manufacturing and its preparation and application

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0059] Select a piece of H13 hot work die steel, whose Ms point is about 350°C, simulate the wear or fatigue cracks, and then grind and groove the damaged area, such as figure 2 As shown, and then perform laser additive repair, which specifically includes the following steps:

[0060] S1: The powder weight is weighed according to the ratio of H13 steel: 304 stainless steel: invar 36 = 50:9:9. After calculation, the chemical composition of the mixed alloy powder is: C: 0.32%; Cr: 6.1%; Ni: 6.1% ; Mn: 0.6%; Si: 0.8%; Mo: 0.9%; V: 0.7%; the balance is Fe and unavoidable impurities, and its Ms point is about 210 ° C. The thermal expansion curve is shown in figure 1 Curve 2.

[0061] S2: The mixing method is ball mill mixing. Put the weighed powder into a mixing bottle containing steel balls. The ratio of balls to materials is 1:10. Wrap insulating tape around the mixing bottle, and then put it in a ball mill roller for mixing for 6 hours. Machine speed is 350r / min.

[0062] S3...

Embodiment 2

[0066] A piece of Q690D steel is selected, its Ms point is about 410℃, and the thermal expansion curve is shown in figure 1 Curve 1, simulating the damage, and then grinding and grooving the damaged area, and performing laser additive repair, which specifically includes the following steps:

[0067] S1: The powder weight is weighed according to the ratio of H13 steel: 304 stainless steel: invar 36: pure iron powder = 32:28:7:16. After calculation, the chemical composition of the mixed alloy powder is: C: 0.2%; Cr: 8.0 %; Ni: 6.1%; Mn: 0.8%; Si: 0.7%; Mo: 0.5%; V: 0.4%; the balance is Fe and unavoidable impurities.

[0068] S2: The mixing method is ball mill mixing. Put the weighed powder into a mixing bottle containing steel balls. The ratio of balls to materials is 1:10. Wrap insulating tape around the mixing bottle, and then put it in a ball mill roller for mixing for 6 hours. Machine speed is 350r / min.

[0069] S3: Fully dry the mixed powder prepared in S2, put it in a dr...

Embodiment 3

[0073] Select a piece of QP980 steel, whose Ms point is about 390°C, simulate its damage, and then polish and groove the damaged area, and perform laser additive repair, which specifically includes the following steps:

[0074] Change the powder preparation ratio in the implementation case to H13 steel: 304 stainless steel: invar 36: pure iron powder = 8:20:6:15, and the chemical composition of the mixed alloy powder is: C: 0.11%; Cr: 8.2%; Ni: 8.1%; Mn: 0.9%; Si: 0.6%; Mo: 0.2%; V: 0.2%; the balance is Fe and unavoidable impurities.

[0075] Then carry out mixing, drying, and laser additive repair according to S2, S3, and S4 in the implementation case 2. Finally, a dense and defect-free filling metal layer is obtained. The residual stress test results of the repaired area are σ1=-137Mpa, σ2=- 265Mpa.

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Abstract

The invention belongs to the field of laser additive manufacturing and repairing, and more specifically relates to an alloy powder for laser additive manufacturing and repairing martensitic steel and its preparation and application. In terms of mass percentage, the alloy powder contains 0.03%-0.4% of C, 6%-10% of Cr, 4%-8% of Ni, 0.5%-1.5% of Mn, 0.6%-1.2% of Si, and the rest The amount is Fe and unavoidable impurities, so that it has a lower martensitic transformation point. Use this alloy powder to repair martensitic steel with laser additives, form martensite structure in the repaired area, and use the volume expansion effect of martensitic phase transformation to offset the thermal contraction caused by cooling the repaired area, resulting in residuals in the repaired area Compressive stress, avoid defects such as deformation and fatigue cracks in repaired parts, improve the timeliness and reliability of repaired parts, and realize "instant repair and use" of damaged parts.

Description

technical field [0001] The invention belongs to the field of laser additive manufacturing and repairing, and more specifically relates to an alloy powder for laser additive manufacturing and repairing martensitic steel and its preparation and application. Background technique [0002] High-strength martensitic steel usually has good plasticity and toughness, excellent fatigue properties, fracture toughness and stress corrosion resistance. It is a very important steel type and is widely used in aerospace, transportation, mold manufacturing and other important fields. Components in these areas often have high manufacturing costs and long replacement cycles. Therefore, it is of great economic and strategic significance to repair non-seriously damaged components in time and restore their service performance. [0003] However, high-strength martensitic steel is prone to cracks during the repair process, and the repair is difficult. The residual stress state in the repaired area i...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22F1/00B22F10/28C22C38/02C22C38/04C22C38/40B33Y70/00B33Y10/00
CPCB22F1/0003B33Y70/00C22C38/40C22C38/02C22C38/04B22F10/00B22F10/32B22F10/34B22F10/36B22F10/366Y02P10/25
Inventor 刘德健孙允森陈浩魏亚风
Owner HUAZHONG UNIV OF SCI & TECH
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