1. External folding feature: spiral layered folding on the outer surface of the steel pipe.Causes:1) There are folds or cracks on the surface of the tube blank.2) The subcutaneous pores and subcutaneous inclusions of the tube blank are serious.3) The surface of the tube blank is not cleaned well or

It is not that the 304L stainless steel cold-rolled plate is not good and does not reach the specified hardness. It is just that the different processes and carbon content cause this state.The so-called 304L stainless steel cold-rolled plate refers to the finished plate rolled by applying huge press

Why do welds crack? What are the types and preventive measures for weld cracks?Weld cracks can be classified in different ways according to their location, size, causes, and mechanisms. According to the conditions of crack formation, they can be divided into four categories: hot cracks, cold cracks,

Hydrogen-induced defects in welds are related to the amount of hydrogen content. When the hydrogen content in the weld is low, hydrogen embrittlement occurs; when the hydrogen content in the weld is high, white spots often appear on the tensile or bending section; when the molten pool absorbs a larg

1. Milling slip or working width changeDuring the milling process, the main reasons for the milling machine to mill or the change of the working width of the steel plate are as follows.(1) The steel plate itself has defects. For example, when the "crescent bend" of the steel plate is large, the plat

1) Thin-walled stainless steel pipes and fittings should not be in direct contact with cement, cement mortar, and concrete. When the pipeline is concealed, anti-corrosion tape should be wrapped around the outer wall of the pipe or plastic-coated thin-walled stainless steel pipes should be used.2) Wh

1. Physical and chemical inspection and analysis1. 1 Macro inspection and microscopic morphology observation: A section of cracked tube with typical cracks was selected to observe the macroscopic characteristics. The cracks were locally distributed along the longitudinal direction of the tube body,

First, the straightness of the hot-rolled boiler tube body after straightening does not meet the requirements.1. Cause analysis: (1) The deflection value is too large or too small. 2) The reduction is too small.2. Treatment method: (1) According to the specifications, materials, and curvature of the

Forming process of steel elbow1. Die forging. For socket welding and threaded tees, crosses, elbows, and other small pipe fittings, the shapes are more complicated and should be manufactured by the die forging process. The die forging blank should be a rolled profile such as a bar, thick-walled pipe

With the continuous development of my country's economy, the country has vigorously developed the energy industry. Long-distance oil and gas pipelines are an important way to ensure energy security. In the process of oil (gas) pipeline anti-corrosion construction, steel pipe surface treatment is one