Metallics SBH359 Bolts 1/2-13 X 4-1/2 Hxbt SS (Box 50)

The SBH359 is 18-8 stainless steel. 18-8 handles general atmospheric corrosion, which is why these get used on chemical and food-processing equipment. If you're in a chloride or marine environment, 316 is the grade to specify instead, since some chemical environments need special corrosion resistant materials.

No. The SBH359 is not Buy American compliant and is not ARRA compliant, with country of origin listed as multiple. For a federally funded job with domestic sourcing language in the spec, you need a domestically produced stainless fastener instead.

Head across flats measures 0.736 to 0.750 inch, so a 3/4 inch wrench or socket is the correct size. The head is a standard hex, not a flange or socket cap.

The SBH359 runs 100,000 to 150,000 psi minimum tensile with a 65,000 psi minimum yield, and hardness of Rockwell B95 to C32. That puts it below a grade 5 or grade 8 carbon steel bolt on strength, which is the normal trade-off for stainless: you buy it for corrosion resistance, not for maximum clamp load. If the joint is strength-critical and dry, a carbon grade 5 or 8 is the better call.

They ship as a box of 50 with an order minimum of 50 each, so it's a full-box purchase rather than loose count. Metallics lists the SBHC and JSBHC series in other sizes and quantities by request if 4-1/2 inch length or this pack size isn't what the job needs.

The box contains bolts only. Nuts, flat washers and lock washers are separate line items, and for a stainless joint you want matching 18-8 stainless hardware so you don't set up a galvanic couple. Order 1/2-13 stainless hex nuts to match the thread.

18-8 stainless threads are prone to galling when run dry under load, and at Rockwell B95 to C32 these are soft enough for it to happen. Use an anti-seize or thread lubricant on assembly and tighten steadily rather than with an impact. Yield is 65,000 psi minimum, so don't torque them to carbon-steel values.