High-frequency straight seam steel pipe is based on the principle of electromagnetic induction and the skin effect, proximity effect and eddy current thermal effect of charges, thereby locally heating the steel at the edge of the weld to a molten state, and realizing butt welding through intergranular bonding extrusion, thereby achieving The purpose of seam welding.

The characteristics of submerged arc welded steel pipes are: the production process of straight seam welded steel pipes is simple, high production efficiency, low cost, and fast development speed. The strength of spiral welded pipes is generally higher than that of straight seam welded pipes.

Surface pitting of submerged arc welded steel pipe welds refers to weld defects where the surface of the weld is partially lower than the normal surface of the weld. It is a common weld surface defect in submerged arc welding.

While welding process, thermal stress, the phase transformation stress, stress and other processing is over the yield limit (Yield strength), so that after cooling the weldment left failed to eliminate the stress.

Focusing on the process of the major industrial countries of the world's welded steel pipe consumption and development , they have experienced a variety of structural adjustment process. When the technology level of welded steel pipe production increase, the cost will decrease, and the industry will develop.

Added to the liquid steel deoxidizing element, which is dissolved in a portion of the metal and the slag deoxidation oxygen into the product and consume oxygen, and the remaining part is absorbed by the liquid steel in order to meet the specifications of the finished steel element requirements.

Ultrasonic inspection of seamless pipes principle

According to the point of metal corrosion process can be divided into chemical corrosion and electrochemical corrosion.

Rockwell hardness of the surface is also very suitable for testing the hardness of the workpiece surface hardening, surface Rockwell hardness scale, there are three to choose from.

When welding steel pipe is firstly liquidation clean welded joints of oil, paint, water, rust, and then based on wall thickness open groove, thick open and thin open smaller (angle grinder)

There are various kinds of carbon steel pipe both in domestic and international markets for your selection. For example, the API steel pipe is one of the popular steel pipes actually. They are widely used to transport gas, oil or water. The API pipe can be classified into seamless steel pipe, ERW steel pipe, submerged arc welded pipe and so forth.

Spiral steel pipe weld gap as too large, then reductions constitute vicinity effect, eddy current lack of heat, poor weld crystal indirect co-occurrence of incomplete fusion or cracking; if the gap is too small, the effect is increased near constitute, excessive heat welding to form welding seam burning;