The inspection of the internal quality of the stainless steel flange is to check the connotative quality of the stainless steel flange itself. It is the quality condition that cannot be found in the appearance quality check. It includes checking the internal shortcomings of the stainless steel flange and checking the mechanical properties of the stainless steel flange. Important parts and large stainless steel flanges should also be analyzed for chemical composition.

Since stainless steel flanges are made into parts, their stress status, importance, and working conditions are different during use, and the materials and metallurgical processes used are also different. Therefore, different parts are made according to the above conditions and in accordance with the requirements of this section. The flange is divided into categories, and different parts and different specifications have different classifications of stainless steel flanges.

For internal defects, we will inspect the stainless steel flanges by low-magnification, fracture inspection, and high-magnification inspection methods to check whether there are internal cracks, shrinkage holes, looseness, coarse crystals, white spots, dendrites, and streamlines that do not conform to the shape and flow. Disadvantages such as line turbulence, flow through, coarse crystal ring, oxide film, delamination, overheating, overburning arrangement, etc. For the mechanical properties, it is mainly to check the normal temperature tensile strength, plasticity, toughness, hardness, fatigue strength, high temperature instantaneous rupture strength, high temperature endurance strength, endurance plasticity and high temperature creep strength.

Stainless steel flanges belong to the fine casting method to produce flanges. This type of casting has a much finer arrangement than ordinary sand casting, and the quality is improved a lot. It is not easy to have problems such as loose arrangement, pores, and trachoma.