xxs:114.3x17.12 seamless steel pipes** Yes (ASME B36.)10m）
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SA335P11 seamless steel pipe cold treatment measures. SA335P11 seamless steel pipe high-carbon steel carbon steel, after heat treatment, there is also a part of low-temperature martensite that is not converted into austenite, which becomes residual martensite in the use of the product, which affects the use characteristics. If it is placed below zero and refrigerated, it can promote the austenite change of residual martensite, so the essence of cold treatment is heat treatment again. The heat-treated in-situ stress at room temperature and the heat-treated in-situ stress at zero degrees are accumulated, and when the overlapping in-situ stress exceeds the strength limit of the raw material, cold-treated cracks will occur.
SA335P11 seamless steel pipe heat treatment after cold treatmentBefore cold treatment, the SA335P11 seamless steel pipe is boiled in boiling water for 30-60min, which can remove 15%-25% heat treatment thermal stress and make the residual martensite relieve aging, and then carry out -60 basic cold treatment, or carry out -120 cryogenic treatment, the lower the temperature, the more residual martensite is converted into austenite, but it is unlikely that all the changes will be completed, the test shows that about 2%-5% The residual martensite is preserved, and a small amount of residual martensite must be preserved, which can relax the in-situ stress and play a regulating role.
The inventory-to-output ratio of steel has also fallen to a historical low, and the lower inventory has made the fundamentals of steel better. In the overall deterioration of the industrial chain, coal and coke enterprises are in a loss-making situation, and only steel companies can turn losses into profits this year, this industry phenomenon is questionable. The author recently learned from the survey of the North China coal and coke industry chain held by Dashang that at present, domestic steel enterprises mainly rely on the purchase of raw iron ore to make profits by purchasing more than the decline in the selling price of finished steel, and get rid of last year's loss. Data show that since the beginning of this year, the international Platts 62% grade iron ore index once fell below 90 US dollars tons, more than one-third of the first year of the year, and the trend of domestic steel prices continued to decline, but the decline was far less than the former. The person in charge of the research steel enterprises told the author that this kind of profitability is only "rich on paper": steel enterprises are indeed profitable under the mode of first-in-first-use, but the steel produced now is produced with iron ore purchased in the early stage, in other words, if the net profit of steel enterprises is calculated by the first-in-first-use production model, there will be a loss. Moreover, under the continuous decline of raw materials such as iron ore and coal and coke, the cost support effect of itself cannot be reflected, let alone the price increase, and the reverse principle of imported SA335 P11 seamless steel pipe rising will drag down steel prices to follow the raw materials in the market outlook.