GB/T9948 seamless steel pipe for petroleum cracking is a seamless pipe suitable for furnace tubes, heat exchangers and pipelines in petroleum refineries. High-quality carbon structural steel, alloy structural steel and stainless heat-resistant steel high-pressure seamless rigid pipes are used to manufacture steam boiler pipes of high pressure and above. These boiler pipes work under high temperature and pressure, and the pipes are exposed to high temperature smoke. Oxidation and corrosion will also occur under the action of gas and water vapor. Therefore, steel pipes are required to have high lasting strength, high oxidation resistance, and good organizational stability. In addition to ensuring chemical composition and mechanical properties, high-pressure boiler pipes must also Carry out hydraulic pressure test one by one, including expansion and flattening tests. High-pressure seamless pipes are delivered in a heat-treated state.
Petroleum cracking pipe production and manufacturing methods:

① Generally, the service temperature of seamless steel pipes is below 450°C. Domestic pipes are mainly made of  No. 10, No. 20, 12CrMo, 15CrMo, 12CrlMo, 12CrlMoV, 12Cr5MoI, 12Cr9MoI, hot-rolled pipes or cold-drawn pipes.

② GB9948 standard seamless steel pipes are often exposed to high temperature and high pressure conditions when used. The pipes will oxidize and corrode under the action of high temperature flue gas and water vapor. Steel pipes are required to have high lasting strength, high resistance to oxidation and corrosion, and good structural stability.

use:

① Generally, seamless steel pipes are mainly used to make water wall pipes, boiling water pipes, superheated steam pipes, superheated steam pipes for locomotive boilers, large and small smoke pipes and arch brick pipes, etc.

②GB9948 seamless steel pipe is mainly used to manufacture superheater tubes, reheater tubes, air guide tubes, main steam pipes, etc. for high-pressure and ultra-high-pressure boilers.

GB9948 standard seamless steel pipes are divided into general boiler pipes and high-pressure boiler pipes according to their high temperature performance. Whether general boiler tubes or high-pressure boiler tubes, they can be divided into various steel pipes according to their different use requirements.
GB/T9948 seamless steel pipe, outer diameter 10~426mm, wall thickness 1.5~26mm. The outer diameter and wall thickness of superheated steam tubes, large smoke tubes, small smoke tubes and arch brick tubes used in locomotive boilers are otherwise specified.

Appearance quality: No cracks, folds, rolls, scabs, delamination and hair lines are allowed on the inner and outer surfaces of steel pipes. These defects should be completely removed. The cleaning depth shall not exceed the negative deviation of the nominal wall thickness, and the actual wall thickness at the cleaning location shall not be less than the minimum allowable wall thickness.