The Properties and Residual Stress of Argon arc Cladding Metal by Low Temperature Martensitic Transformation Powder

Resumo

Martensitic Fe-based metal was achieved by argon arc surface cladding using self-developed low-temperature phase transformation (LTT) powders. Residual stress (RS), retained austenite (RA) content, hardness and wear resistance of the cladding layer under different powder compositions were tested. Meanwhile, the phase composition, microstructure and wear mechanism of the cladding metal were also analyzed. The results show that under suitable process parameters, the cladding layer and the substrate are metallurgical bonding without crack and porosity. The microstructure of the cladding layer is mainly lath martensite with less RA distributed on. Due to the volume expansion during phase transformation from austenite to martensite at about 200°C degree, large compressive RS is produced within the cladding metals, which has effectively compensated the tensile RS result from thermal shrinkage. The compressive RS reaches maximum of -361 MPa, and the average RA in the cladding layer is 10.85% for powder with composition of 10% Cr and 8% Ni. The hardness of the cladding layer is 2.6 times higher than that of the matrix material, which could reach up to 557.2 HV. The wear resistance of the surface cladding layer is nearly 57 times higher than that of the base material, which has the most excellent comprehensive performance.