Study on the Weldability of ZG30Cr06A Needling Material
ZG30Cr06A as a newly developed material is made into needling of mining machinery’s hydraulic support. Its tensile strength is up to 800MPa. In the paper, the weldability of ZG30Cr06A was thoroughly studied. The sensitivity to cold crack of ZG30Cr06A was tested by means of maximum hardness of HAZ and Y-slit type cracking test. And the variation of microstructure and properties of weld joints under different welding energy conditions was studied. The results show that ZG30Cr06A steel has a certain cold crack and hot crack tendency and a little reheat crack sensitivity in welding. Embrittlement and softening often appear in the HAZ. When the workspaces of 30mm were welded at room temperature, the maximum hardness of HAZ was up to 389HV. And the joints have a tendency to quenched hardening and bigger sensitive to cold crack. The welded joints would not produce cold crack when the preheat temperature is up to 120°C in welding. Because there is more influence of welding energy input on the microstructure and properties of joint, so in order to avoid the appearance of embrittlement and softening in HAZ and ensure weld quality, the welding energy input of ZG30Cr06A steel whose thickness is 30mm should be controlled less than 40 kJ/cm during the welding.
L. Yang et al., "Study on the Weldability of ZG30Cr06A Needling Material", Advanced Materials Research, Vols. 314-316, pp. 304-307, 2011