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Alloy powder for repairing martensitic steel through laser additive manufacturing and preparation and application of alloy powder

An alloy powder, laser additive technology, applied in the directions of additive manufacturing, additive processing, process efficiency improvement, etc., can solve the problems of poor repair effect, unable to obtain the compressive stress of repaired area, etc., to offset thermal shrinkage and shorten powder milling Period, the effect of expanding the scope of application

Active Publication Date: 2020-07-10
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 through laser additive manufacturing and preparation and application of alloy powder
  • Alloy powder for repairing martensitic steel through laser additive manufacturing and preparation and application of alloy powder
  • Alloy powder for repairing martensitic steel through laser additive manufacturing and preparation and application of alloy powder

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0059] Choose a piece of H13 hot-work die steel whose Ms point is about 350℃ to simulate wear or fatigue cracks, and then polish and groove the damaged area, such as figure 2 As shown, the laser additive repair is then performed, 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, its Ms point is about 210℃, and 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 ball-to-material ratio is 1:10. The mixing bottle is wrapped with insulating tape, and then placed in the ball mill drum for mixing for 6 hours. The machine speed is 350r / min.

[0062] S3: Ful...

Embodiment 2

[0066] Choose a piece of Q690D steel, its Ms point is about 410℃, and the thermal expansion curve can be seen figure 1 Curve 1, simulating the damage, and then grinding and grooving the damaged area for laser additive repair, which specifically includes the following steps:

[0067] S1: The powder weight is weighed at 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 ball-to-material ratio is 1:10. The mixing bottle is wrapped with insulating tape, and then placed in the ball mill drum for mixing for 6 hours. The machine speed is 350r / min.

[0069] S3: Fully dry the mixed powder prepared by S2, and put it in a drying box for drying at a ...

Embodiment 3

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

[0074] The powder preparation ratio in the implementation case is changed to H13 steel: 304 stainless steel: invar 36: pure iron powder = 8: 20: 6: 15, 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 perform mixing, drying, and laser additive repair according to S2, S3, and S4 in Example 2, and finally a dense and defect-free filler metal layer is obtained. The residual stress test result of the repair area is σ1=-137Mpa, σ2=- 265Mpa.

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Abstract

The invention belongs to the field of laser additive manufacturing repair, and particularly relates to alloy powder for repairing martensitic steel through laser additive manufacturing and preparationand application of the alloy powder. The alloy powder contains the following components of, in percentage by mass, 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 thebalance Fe and inevitable impurities, so that the alloy powder has a relatively low martensite phase transformation point. The alloy powder is used for repairing the martensitic steel through laser additive manufacturing, a martensitic structure is formed in a repaired area, the volume expansion effect of martensitic phase transformation is used for counteracting heat shrinkage generated by cooling of the repaired area, residual compressive stress is generated in the repaired area, the defects of deformation, fatigue cracks and the like of repaired parts are avoided, timeliness and reliability of part repairing are improved, and the damaged part can be used immediately after being repaired.

Description

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

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F1/00B22F3/105C22C38/02C22C38/04C22C38/40B33Y70/00
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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