The fracture of the 9Cr2Mo steel cold rolling roll is classified as hydrogen embrittlement fracture, with the crack initiation site located at the circular spots inside the roll where hydrogen accumulates. High hydrogen content and large quenching stress caused by delayed tempering are the main causes of hydrogen embrittlement fracture of the roll, while severe dendrite segregation and abundant inclusions accelerate the fracture. The recommendations are as follows:① Improve metallurgical quality to reduce the content of inclusions and the degree of segregation in the steel;② Increase the forging ratio to avoid dendrite segregation in the material;③ Prolong the hydrogen diffusion time to reduce the hydrogen content of the roll;④ Conduct tempering in a timely manner to reduce the quenching stress of the cold rolling roll.
IntroductionRaise boring machines are among the key pieces of equipment used for mining in underground mines. As the core component of the machine, the drill pipe is subjected to significant pressure and friction, and is frequently eroded by dust and water during operation. The failure of drill pipe
GH4169 alloy is a solid solution aging strengthened nickel based deformation high-temperature alloy with γ 'and γ' 'as the main strengthening phases. This alloy has multiple types of elements, high degree of alloying, and good comprehensive properties such as high strength and good plasticity.
