Application of 42CrMo Seamless Steel Pipe in Oil Pipe

It relates to a 42CrMo seamless steel pipe and a production method thereof, and the yield strength of the anti-hydrogen sulfide corrosion tubing and casing can reach 130-140ksi.

The main process of the traditional production of 42CrMo seamless steel pipe is: selecting the appropriate steel grade, smelting, casting and rolling into a hot-rolled seamless steel pipe, then performing overall quenching and tempering heat treatment, and finally making it resistant to hydrogen sulfide stress corrosion by proper mechanical processing use oil casing and tubing.

Compared with general-purpose petroleum casing and tubing, 42CrMo seamless steel pipe and tubing have many special features in material selection and production technology. Its main feature is strict control of chemical composition and heat treatment process.

In order to ensure the resistance to hydrogen sulfide stress corrosion, the quenching and high temperature tempering heat treatment process is generally selected, and the tempering temperature is as high as possible below Ac 1 to ensure that the finished steel pipe has good hardness uniformity and low residual stress.??There are two main considerations in the composition design. One is to add elements that can improve the hardenability and tempering stability to ensure that the material can get as much martensite structure as possible after quenching, and has a higher tempering temperature during tempering, such as C, Mn, Cr, Mo, B, etc. Second, the elements that are prone to form inclusions and segregation should be strictly controlled, such as P, S, O, N, etc., and calcium treatment should be performed to ensure higher resistance to hydrogen sulfide stress corrosion.

From the perspective of steel grade, the higher the steel grade of the material, the more elements that improve hardenability and tempering stability need to be added to ensure that higher strength can still be obtained at higher tempering temperatures.. However, for high-grade H2S-resistant SCC tubing and casing, the alloying elements added to ensure the strength may reduce the H2S SCC resistance while ensuring the strength of the steel. For example, higher Mn may cause more serious segregation, higher Cr may produce coarse carbides, and higher C may also produce higher tempering hardness. The addition of a large number of alloying elements will increase the strength while reducing the resistance to hydrogen sulfide stress corrosion. This is a difficult problem encountered in the development of high steel grade hydrogen sulfide stress corrosion resistance oil casing.

Therefore, most manufacturers can only produce H2S stress corrosion resistant tubing and casing with steel grade below 110ksi. As for the resistance to hydrogen sulfide stress corrosion oil casing of steel grade above 125ksi, because its yield strength is above 862MPa and the hardness is above HRc 32, its hydrogen sulfide stress corrosion sensitivity value is higher, making production more difficult. Therefore, so far, only the SM-125S sulfur-resistant casing produced by Japan's Sumitomo Metals in 2004 has been used in the North Sea Oilfield.

Regardless of the material, it must meet the requirements. If it meets the requirements, it is best to have the lowest price. So how to judge the quality of 42crmo seamless steel pipe? It can be judged in three steps.?

1. Choose according to qualityWhen choosing 42CrMo seamless steel pipe, you must first choose a good quality steel pipe. The judgment of the quality of the steel pipe is actually a good judgment, mainly from the welding method of the steel pipe. The quality of general steel pipes is not only a problem with the selection of steel pipes, but also has a great relationship with the welding process of the steel pipes. Therefore, when choosing a good quality steel pipe, we must start from its workmanship.??2. Product aestheticsIn the process of choosing to use steel pipes, it is generally necessary to pay attention to its aesthetics. General steel pipes are used in many occasions. For some occasions, the appearance of 42crmo seamless steel pipes is very strict, and the steel pipes are required to have a certain aesthetics, so that they can be used for the users in the process of using steel pipes. Good benefits come.

3. Choose qualified manufacturersWhen users choose 42CrMo seamless steel pipes to use, they must also pay attention to choosing a good manufacturer, because there are many seamless steel pipe manufacturers in order to make profits, so there is no good guarantee for the quality of 42CrMo seamless steel pipes. So at this time, in order to choose a good quality steel pipe, you must choose a good manufacturer to buy the steel pipe, so that the steel pipe can be used for a longer time.

Steel pipe industry practitioners at Permanent Steel Manufacturing Co.,Ltd, knowledge enthusiasts