LITTLE P.ENG. FOR ENGINEERING CONSULTANCY SERVICES

Requirements for bolting are provided in para. 309. Listed bolting is acceptable. The only relevant component standards are ASME Bl.l, Unified Inch Screw Threads (UNand UNR Thread Form). ASME B 18.2.1, Square and Hex Bolts and Screws (inch series), and ASME B 18.2.2, Square and Hex Nuts (inch series). Table A-2 in ASME B31.3, Appendix A provides listed boiling material specifications. Unlisted bolting (i.e., not listed in Table A-2) are subject to the requirements of para. 30

Monitoring of the actual residual bolt load after tightening is essential to ensure that leak-tightness goals are achieved and becomes an important part of the quality assurance process of achieving flange joint integrity. All tightening methods provide a degree of stud-preload scatter as a function of their process capability. The only way to be sure that specified stud preload is achieved is to measure it. There are several methods for performing stud-stretch measuring, inc

Bolts and nuts should be selected to conform to the design specifications set out with the flange design. Care is taken to ensure that the correct grade of material is selected to suit the recommended bolting temperature and stress ranges. Material specifications for bolts are outlined in BS 4882 and ASME Section VIII. Common material specifications for bolts and nuts are shown in Table A7.17. The following information should be specified when ordering bolts and nuts: Quantit

The function of a bolt is to provide a clamp load or preload (Fp) to sufficiently compress and stress the gasket and resist the parting forces exerted by the hydrostatic end force and other external loads. The hydrostatic end force is created by the pressure of the internal fluid across the internal area of flange. The internal area is generally the inside diameter of the sealing element. All bolts behave like a heavy spring. As you turn down the nut against the flange, the b

Bolting Bolting material for cast-iron flanges is listed in ASME B16.1. Generally, ASTM A307, grade B material is suitable. For steel flanges, acceptable bolting material is listed in ASME B16.5. Threading. Bolts and nuts normally are threaded in accordance with ASME B1.1 Standard for Unified Screw Threads. In diameters 1 in and smaller, Class 2A fits on the bolt or stud and Class 2B on the nut applies with the coarse thread series. In diameters 1¹⁄₈ in and larger, the eight-