Expansion joint is widely used in the bellows industry, and its fatigue test is a must in the bellows industry. The bellows type testing machine produced by platinum detector is widely used in the bellows industry.
General provisions
1. The quality and specifications of the materials used for expansion throttling shall conform to the relevant provisions of national standards and industry standards. The material production unit must guarantee the quality and meet the following requirements.
1.1 materials quality certificate (original) shall be provided in accordance with the relevant standards. The contents of the material quality certificate must be complete and confirmed by the quality inspection department of the material production unit with the seal.
1.2 make clear and firm marks on the designated parts of the material according to the relevant standards.
1.3 the manufacturer of expansion joint shall check and accept the steel according to the material quality certificate. Before production, check the quality certificate documents, batch number of furnace and mark of material number carefully. And according to the relevant standards, carefully check the surface quality of materials, unqualified can not be put into use.
1.4 materials used for the manufacture of expansion joints shall be reinspected in accordance with article 6 of the pressure vessel safety technical supervision regulations (90th edition) before use if they are qualified.
1.5 during the manufacturing process of expansion joints, the following provisions must be followed to make mark transplantation, so as to ensure the tracking of user identification and query.
1.6 hard marking is prohibited on the material of bellows (including material marking, welder inspector and unreported test mark).
1.7 the bellows shall be manufactured by drawing a distribution map of marks, defining the material marks and other marks (the map shall be stored in the quality file), and the expression of the distribution map shall be determined by the manufacturer itself.
1.8 when foreign steel is used to make expansion joints, it shall be the material permitted by foreign standards for pressure vessels. The scope of use shall conform to the relevant standards, and there shall be a quality certificate of the material.
2, steel plate,
2.1 in addition to the relevant requirements of chapter 4 "materials" and appendix A "supplementary provisions on materials" of gb150-89, expansion joint steel shall also comply with the provisions of this standard.
2.2 materials and codes used for expansion joints shall be in accordance with table 5-1, and their chemical composition and mechanical properties shall meet the requirements of relevant national or industrial standards.
2.3 corrugated pipe austenitic stainless steel material should be soft, for the use of austenitic stainless steel plate manufacturing corrugated pipe in general according to GB4237 selection, the thickness of steel plate is greater than 4mm, when according to GB4237 selection, should indicate the pressure vessel steel plate. If the thickness of the plate is less than or equal to 4mm, the surface quality of the plate should be NO.2B or NO.2D when the plate is selected according to GB3280.
2.4 carbon Italian steel and low alloy steel (smelting analysis) and non-vessel steel with a carbon content greater than 0.25% shall not be used to make expansion joints.
2.5 carbon steel bellows with wall thickness less than 6mm shall be made of 20HP steel plate.
2.6 pressure vessels with a volume greater than 10m3 shall not use Q235A material to make expansion joints.
2.7 the bellows shall be made of 20g steel plate. When the thickness is less than or equal to 16mm, one piece of the steel plate shall be taken for each batch for re-inspection of tensile strength, yield point, elongation and impact work at room temperature (v-notch) according to appendix G of GB15089.