When conducting pipeline construction, the direction of the pipeline needs to be changed by using elbows. Elbows can be classified into many types based on their own angles and materials. Common ones include15Degree and90Elbows can be classified into carbon steel elbows and stainless steel elbows based on the materials used. Plastic elbows, etc.
Among all types of elbows, stainless steel elbows are a very common one. Due to the special nature of stainless steel elbows, they have a wide range of applications and excellent performance. Of course, even if the yield rate of factory production is guaranteed, some stainless steel elbows may still have certain defects. So, how can the welding quality of stainless steel elbows be inspected? Let's take a look together!
Inspection methods for welding quality of stainless steel elbows
1.Non-destructive testing
Detect defects in welding such as inclusions, pores and cracks. The most commonly used one now isxRadiographic examination, ultrasonic examination and magnetic examination.xRadiographic testing utilizes rounded cornersxRadiography technology determines whether there are defects based on the negative images.
Then, evaluate whether the welding is qualified or not based on the technical requirements of the product. The basic principle of ultrasonic flaw detection is that the detector emits ultrasonic waves and transmits them to the metal. When ultrasonic waves are transmitted to the interface between metal and air, they refract and pass through welding.
When there are defects in the welding, the ultrasonic waves are reflected and received by the detector, and the reflected waves appear on the screen. By comparing and identifying these reflected waves with the usual waves, the size and location of the defect can be determined. Ultrasonic examination ratioxRadiographic examination is simple and 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 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 sometimes5-20Observe with a magnifying glass. Surface defects of welded elbows can be detected through visual inspection. Such as undercutting, welding protrusions, pores, flux, surface cracks, welding penetration depth, etc. The shape and size of the fillet can also be measured by a fillet detector or template.
3.Mechanical property test of elbows
Non-destructive testing can detect defects in welding and may require tensile, impact and bending tests of the welded joint.
These tests are carried out by the test team. It is best to weld the test board to the longitudinal joint of the cylinder to ensure consistent construction conditions. In actual production, new steel welded joints are only tested in this area.
4.Hydrostatic test and pneumatic test
For pressure vessels that require sealing, in order to check the sealing of the weld bead, hydrostatic tests or pneumatic tests need to be conducted.
The method is to inject a pressure equivalent to the working pressure of the container1.25Double to1.5Purified water or gas with multiple working pressures(Mainly air). After maintaining for a period of time, observe the pressure drop inside the container. Observe the external leakage phenomenon and evaluate the quality of the welding.
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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.
