In piping systems, elbows are pipe fittings used to change the direction of pipes. According to the Angle of the elbow, the most commonly used elbow is45°,90°and180°According to the engineering requirements, it can also include elbows of other angles (for example60°" Now let me introduce to you the quality inspection methods for stainless steel elbow welding
1.Non-destructive testing
At present, the most commonly used method for detecting defects in weld seams, such as inclusions, pores and cracks, isXRadiographic testing, ultrasonic testing and magnetic flaw detection.XRadiographic testing is carried out by using weld seamsXRadiographic technology is used to determine whether there are defects, how many defects there are and their types.
Then, based on the technical requirements of the product, assess whether the weld seam is qualified. When ultrasonic waves are transmitted to the interface between the metal and the air, they refract and pass through the weld seam. The basic principle of ultrasonic flaw detection is that the probe emits ultrasonic waves for flaw detection and transmits them to the metal.
If there are defects in the weld seam, the ultrasonic waves will be reflected on the probe and received, and the reflected waves will appear on the screen. By comparing and identifying these reflected waves with ordinary waves, the size and location of the defect can be determined. Because ultrasonic testing has a higher ratioXRadiographic testing is much simpler, so it has been widely used.
However, ultrasonic flaw detection can only be judged based on operational experience and cannot be used as the basis for inspection. Magnetic force flaw detection can also be used to detect internal defects and small cracks on the welding surface.
2.Visual inspection
It is usually observed with the naked eye, and sometimes5-20By observing with a magnifying glass and conducting visual inspection, surface defects of the welded elbow can be detected, such as undercut, surface cracks, pores, inclusions and weld penetration depth, etc. The shape and size of the weld can also be measured with a welding joint detector or template.
3.Mechanical property test of elbows
Sometimes it is necessary to conduct tensile, impact and bending tests on welded joints. Non-destructive testing can detect defects in the weld seam, but it cannot explain the mechanical properties of the metal in the heat-affected zone of the weld seam.
These tests were conducted using test plates, which were preferably welded to the longitudinal joints of the cylinder to ensure consistent construction conditions. Then the mechanical properties of the test plate are tested. In actual production, only new welded joints are tested in this field.
4.Hydrostatic test and pneumatic test
For pressure vessels that require sealing, hydrostatic tests and pneumatic tests should be conducted to facilitate the inspection of the sealing of the welds and their pressure-bearing capacity.
The method is to inject the equivalent of working pressure1.25to1.5When purified water or gas (mainly air) at twice the working pressure is left for a period of time, then we observe the pressure drop in the container and the external leakage phenomenon, which can assess whether the weld seam is qualified.
Foshan Weilihuang Trading Co., Ltd. is a leading manufacturer specializing in the production and sales of international and domestic stainless steel hardware accessories and its own brands. The company is located at Tianjinli Hardware Accessories Center, Lanshi 2nd Road, Chancheng District, Foshan City, Guangdong Province8seat10-12The number (i.e., the main entrance of the market) has an abundant supply of goods, a complete range of varieties, wide coverage, favorable prices, and stable and superior quality!
The company uses high-quality stainless steel and exquisite craftsmanship to ensure there are no weld marks at the interfaces. Its products feature novel designs, elegant craftsmanship, and long-lasting durability. The company has always adhered to the principle of quality first and reputation first. It is equipped with mature production facilities and has strong technical strength, thus ensuring the quality of its products. The company is willing to make unremitting efforts to join hands with our customers to create a win-win situation and provide high-quality products for our partners.
