Requirements and characteristics of raw materials

Requirements and characteristics of raw materials for nuclear grade 1 pipe fittings

1 the tensile strength of raw material manufacturers is often used as the basis for evaluating metals

the manufacturer of raw material steel pipes used for nuclear grade 1 pipe fittings must obtain the manufacturing qualification license of nuclear safety umbrella equipment. The manufacturer and supplier of raw materials shall be approved by the owner and the Design Institute in advance. The manufacturer of raw materials is a domestic manufacturer

the manufacturers of raw steel pipes used for hydrogen pipe fittings are agreed in advance in the technical conditions for pipe fittings procurement. Generally, the agreed manufacturers are steel mills in the United States, Western Europe or Japan

2 characteristics of raw materials

(1) chemical composition. The chemical composition of nuclear grade 1 pipe fittings should also meet the following requirements on the basis of meeting RCCM m3317: the cobalt content of smelting analysis should not exceed 0.20%, preferably not more than 0.10%. The boron content of the finished product shall not exceed 0.001 8%

in addition to meeting astma403 standard, the chemical composition of hydrogen pipe fittings should also meet the following requirements: phosphorus content and sulfur content of finished product analysis. Therefore, satisfactory results can be obtained by adopting quasi-static fatigue analysis method. The quantities should be

(1) chemical composition respectively. On the basis of meeting CCM m3317, the chemical composition of nuclear grade 1 pipe fittings should also meet the following requirements: the cobalt content of smelting analysis should not exceed 0.20%, preferably not more than 0.10%. Li Chao, the "finished product", also believes that the bright content of the analysis should not exceed 0.001 8%

in addition to meeting astma403 standard, the chemical composition of hydrogen pipe fittings should also meet the following requirements: the phosphorus content and sulfur content of the finished product should be f more than 0.030% and 0.020% respectively

(1) chemical composition. The chemical composition of nuclear grade 1 pipe fittings should also meet the following requirements on the basis of meeting RCCM m3317: the cobalt content of smelting analysis should not exceed 0.20%, preferably not more than 0.10%. The boron content of the finished product shall not exceed 0.o01 8%

in addition to meeting astma403 standard, the chemical composition of hydrogen pipe fittings should also meet the following requirements: the phosphorus content and sulfur content of finished products should be

(2) mechanical properties respectively. For nuclear grade 1 pipe fittings, RCCM m3317 requires that materials with elongation less than 45% need to undergo a low-temperature impact test at.40 ℃. The procurement technical conditions also require that a high-temperature tensile test at 350 ℃ be added to RCCM m3317

the mechanical properties of hydrogen pipe fittings can meet the ASTM A403 standard, and only room temperature tensile test is required

(3) metal longitudinal weave inspection. For nuclear grade L pipe fittings, the grain size test is required in RCCM m3317, and grade 2 or finer is qualified. Hydrogen pipe fittings, metal longitudinal texture inspection required in the procurement technical conditions, including non-metallic inclusion inspection and grain size inspection. The non-metallic inclusions are required to be inspected according to ASTM E45 standard. The inspection results of non-metallic impurities of class A, B, C and D are not more than grade 2.5 respectively, and the total is not more than Grade 7., The particle size of the product is required to be tested according to astmel L2 standard, and the test result is qualified if it is at level 4 ~ 7

(4) product corrosion test., Nuclear grade 1 pipe fittings and hydrogen pipe fittings are required to carry out the quality corrosion test. The quality corrosion test standards are RCC, m mcl300 and ASTM a262 e method respectively. The requirements in these two standards are similar. Both require that the sensitized samples be soaked in a predetermined amount of boiling copper sulfate sulfuric acid solution for a certain time, and then bend the Nfix ii/nflex/ngarde device by the central rod bend test of titanium alloy to detect whether they have the tendency of crystal corrosion