CAJ | 학술논문

研究在使用过程中钻井牙轮提前断裂的原因.牙轮的材料为20Ni_4Mo,热处理工艺为气体渗碳再进行780 ℃淬火+低温回火.利用化学分析、金相检验、硬度计及扫描电镜等方法对20Ni_4Mo渗碳钢制矿用牙轮的断裂原因进行了分析.结果表明:牙轮断裂的主要原因为渗碳及热处理工艺不当,另一原因是牙轮基体存在硫化物等非金属夹杂物.为了检验牙轮的淬火工艺,将20Ni_4Mo钢原材料分别在780和850 ℃进行淬火实验,结果证明780 ℃淬火工艺不合理.
연구재사용과정중찬정아륜제전단렬적원인.아륜적재료위20Ni_4Mo,열처리공예위기체삼탄재진행780 ℃쉬화+저온회화.이용화학분석、금상검험、경도계급소묘전경등방법대20Ni_4Mo삼탄강제광용아륜적단렬원인진행료분석.결과표명:아륜단렬적주요원인위삼탄급열처리공예불당,령일원인시아륜기체존재류화물등비금속협잡물.위료검험아륜적쉬화공예,장20Ni_4Mo강원재료분별재780화850 ℃진행쉬화실험,결과증명780 ℃쉬화공예불합리.
The failure analysis of a drilling cone,that was suddenly broken at work,was conducted. The cone was made of 20Ni4Mo steel and was carburized in Acetone gas. It was reheated to 780 ℃ and oil quenched for tempering at low temperature (200 ℃). The failed (or failure) cone was investigated with chemical analysis, morphology examination, hardness measurement and scanning electron microscopy. The results showed that the main factor responsible for the cone fracture was the discontinuity of the microstructure and the hardness of the material, which was caused by improper carburizing and heat treatments. Besides, non-metal inclusions, such as sulphide particles in the matrix, might also lead to the fracture of the bit. In order to optimize the quenching process for the cone, 20Ni4Mo raw materials samples were quenched at different temperatures. It was shown that 780 ℃-quenching temperature was unreasonable.