日韩伦理中文字幕_国产欧美一区在线观看_av片在线观看_电车痴汉在线观看_粉嫩av一区二区三区四区_国产超碰91_人妻丰满熟妇岳av无码区hd_调教卵蛋囊袋玩虐精奴_波多野结衣丝袜诱惑_免费特级黄色片_国产igao激情视频入口_国产欧美一区二区三区在线看蜜臂_日本色图在线_91porn在线_h喷水荡肉失禁爽高h在线观看

Stainless steel head in the heating and cooling process, the cooling rate is inconsistent surface and center and time, forming temperature, resulting in volume expansion and contraction of the uneven stress that the heat stress. Stainless steel head under the effect of thermal stress due to a temperature below the surface began to core section, leaving the central portion is greater than the contraction also central portion tension, when the end of the cooling, since the cooling core section final volume shrinkage can not freely leaving the surface layer by Ministry press center of tension. That is under the influence of thermal stress and finally to the workpiece surface pressure and heart Ministry tension. This phenomenon is cooled velocity, material composition and heat treatment and other factors.

 

When cooled, the faster, the higher the carbon content and alloy composition, inhomogeneous plastic deformation of the cooling process in the thermal stress generated by the larger, the final form of the residual stress is greater.

On the other hand the steel during heat treatment due to the change in the organization that is the transformation of austenite to martensite, accompanied by the increase of the specific volume of the volume expansion of the workpiece, the various parts of the workpiece has a phase change, resulting in inconsistency of the volume of tissue grown stress.

 

The end result stainless steel head the surface tissue stress is tensile stress, the heart portion compressive stress, and thermal stress exactly the opposite. The stress in the workpiece size and cooling rate of martensite transformation zone factor, shape, chemical composition of the material.