A flange is a disc-shaped part that is most common in plumbing engineering.It is the part that connects the pipes to the pipes. Connect to the pipe end. There are holes on the flanges for bolts to connect the two flanges tightly. The flanges are sealed with gaskets.

The medium used for quenching and cooling of seamless steel pipes is called quenching cooling medium (or quenching medium). The ideal quenching medium should have the condition that the steel can be quenched into martensite without causing too much quenching stress.The commonly used quenching media for quenching and cooling of seamless pipes are water, aqueous solution, mineral oil, molten salt, molten alkali, etc.

Submerged arc welding is an important welding method. Its inherent advantages of stable welding quality, high welding productivity, no arc and little smoke make it an important steel structure in the production of pressure vessels, pipe sections, box beams and columns. the main welding method.

Hydrogen embrittlement is usually manifested as a significant decrease in the plasticity of steel, a sharp increase in brittleness, and a tendency to rupture after a period of time under static load (often lower than the σb of the material).

The heat treatment of 35crmo seamless steel pipe generally adopts solution heat treatment, the so-called annealing, and the temperature range is 1040~1120℃ (Japanese standard). It can also be observed through the observation hole of the annealing furnace. The 35crmo seamless steel pipe in the annealing zone should be incandescent, but without softening and sagging.

Inward folding is a common quality problem in the production of seamless steel pipes. It is the irregularly distributed sheet-like folds and spiral-like folds on the inner surface of the steel pipe, and the edges of the defects are mostly serrated. The cause is generally the residual shrinkage cavity and intermediate porosity of the blank.