What surface finish requirement is called for when mounting MM valves?
A. The original Goyen Tech Spec CAS-3 stipulates surface finish to SA 1163. When the MM group of products were first put on the market, a suitable specification was hard to establish. The AS 1163 only goes part the way to satisfying an adequate body to header mounting arrangement. The following passages of the specification are the only valid information and are written as follows: Section 10: Freedom of Surface Defects The section shall be free from lamination, surface flaws and other defects detrimental to its use for structural purposes. Section 11: 11.1 Grinding When removal of surface defects by grinding is adopted, the ground area shall be well flared and the remaining wall thickness in the ground area shall be not less than 90% of the nominal thickness. 11.2 Depositing weld metal Welding used in the repair of surface defects shall be performed in accordance with AS 1554.1, using low – hydrogen electrodes compiling with AS 1553. Welds shall be sound the weld metal being thoroughl
