Determination of titanium for vessels - part 2

Determination of titanium for vessels

(6) the chemical composition and mechanical properties of titanium materials in China are not the same as those of corresponding brands abroad, but there is a good corresponding relationship. It is allowed and convenient to use foreign titanium materials to replace domestic titanium materials of corresponding brands At this time, in addition to meeting the requirements of Article 22 in the supervision regulations on safety technology of pressure vessels, when the strength of foreign titanium materials is slightly different from that of domestic titanium materials, the allowable stress value shall also be adjusted accordingly

When it is necessary to use titanium materials other than titanium grades and states specified in this standard and newly developed titanium materials to manufacture vessels due to special circumstances, the following conditions shall be met at least in addition to the provisions in Article 23 of the supervision regulations on safety technology of pressure vessels:

1 the chemical composition meets the requirements of corresponding titanium material standards;

2 the room temperature tensile strength, the specified residual elongation stress and the lower line value of elongation are all guaranteed values;

3. It is generally required that the elongation of deformed titanium materials at room temperature shall not be less than 18%. Only when it is confirmed that titanium materials are only used for container components with no deformation or small deformation, and can be formed smoothly with the approval of the manufacturing department, can titanium materials with low elongation be used. At this time, the elongation shall not be less than 15%

4. The titanium material has the tensile strength at the design temperature of the container and the lower line guarantee value data of the specified residual elongation stress

(7) the six grades of deformed titanium listed in this standard have a certain application foundation in China

Before 1993, there were only TA1, TA2 and TA3 grades of titanium used in some containers in the titanium material standards. Basically, TA2 was used as the basic grade. TA1 was used when the plasticity and corrosion resistance were higher, and TA3 was used for the unchanged components. Although TA0, ta9 and TA10 were formally listed in the standards after 1993, the American brand GRADEL equivalent to TA0 has been used in China, Ta9 and TA10 have also been widely used in vessels with the unofficial grades of ti-0.2pd and ti-0.3mo-0.8ni. The two grades of cast titanium have been listed in national standards since 1986 and have been widely used

Therefore, the titanium for containers determined in this standard has accumulated more experience in the production and supply of titanium materials, container manufacturing and application, and has a solid foundation

(8) in addition to the six grades in GB / t3620, titanium plate ta1-a for plate heat exchanger is listed according to GB / t14845-1993, which has good deep drawing performance