Application And Investigation On1Cr11Ni2W2MoV Martensite Stainless Steel Fabricated By Laser Solid Forming

Laser Solid Forming (LSF) is an advanced manufacturing technology, which was developed from rapid prototyping (RP) and laser cladding. Coaxial powder feeding is adopted and metal powder deposited layer by layer in LSF. A density metal component could be rapid fabricated by metal powder feeding additively.The components fabricated by LSF have better or equivalent mechanical properties. Component of1Cr11Ni2W2MoV martensite stainless steel fabricated by LSF was studied in this paper, such as the processing of forming, microstructure and mechanical properties.The effect of processing parameters such as laser power, scanning speed, the powder feeding rate,overlapping on1Cr11Ni2W2MoV martensite stainless steel in laser solid forming was studied.With the laser power increases,single cladding height increases at first then follows and single cladding width decreases always; With the scanning speed increases, both single cladding height and width decrease; With the powder feeding rate increases, single cladding height increases and single cladding width unchanged. The cladding layer has a well flatness when overlapping around30%.Processing parameters and preheating has an effect on cracks’formation in cladding layer. We found that with the increase of laser power and scanning speed,cracks in the cladding layer increases; It has no obvious change about the amount of crack when the powder feeding rate differs; after preheating at300℃, cracks decrease.The results show that after laser solid forming there are the matrix zone, the cladding layer zone and the heat affected zone formed; the matrix zone keeps the original microstructure of the parent metal, and the heat affected zone can be roughly divided into coarse grain zone, fine crystalline and tempering zone. The structure of the cladding layer is plate martensite; Micro-hardness test shows that the hardness of the cladding layer is high and the hardness of the matrix zone is low.The effect of different heat treatment on microstructure and hardness was investigated. The results show that the microstructure has no obvious change, the number of carbides increased and the hardness of every regions decreased after temping heat treatment;After solution heat treatment, austenitizing occurs in every regions of sample and evenly distributed martensite acquired in subsequent air cooling;as the solution temperature increase, grains has the trend of grown and coarse tempering martensite was found and the hardness decrease but ’evenly distributed in different regions of sample by temping after solution heat treatment compared to solution heat treatment.Mechanical properties tests showed that after temping at700℃, the tensile specimen with cladding layer got optimal mechanical properties which its tensile strength σb=704.1MPa and elongation δ=20.66%. Compared with matrix tensile specimen in the same heat treatment, the strength was considerably and elongation reached80%.