Correct Use of Stainless Steel Bolts for Pressure Vessel Applications Available to Purchase

Stainless steel bolts are sometimes specified for pressure vessel applications which are designed according to ASME Section VIII, Div. 1¹ or Div. 2². The design of the flanges and bolting falls under ASME B16.5³ and B16.47⁴ for standard flanges, and under Mandatory Appendix 2 and Para. 4.16 of Division 1 and Division 2 respectively for designed flanges. Stainless bolts have various grades and classes based on material and heat treatment, and size requirements. If special service requirements apply such as meeting NACE standards for wet sour services (namely NACE MR0175 or MR0103)^5,6, it can become impossible to meet both the Code and NACE requirements with stainless steel bolts in many situations.

This paper provides information as follows.

1. The paper incorporates flow charts outlining selection of stainless bolts for flanges on pressure vessel to be constructed according to ASME Section VIII, Divisions 1 and 2.

2. Discusses material test requirements and size limits applicable for each class of stainless bolts used on standard and custom designed flanges.

The paper will help the Code user to select proper grade and type of stainless bolts and avoid non-compliances.