ASTM Specifications

REFERENCE

ASTM A193 MECHANICAL / CHEMICAL REQUIREMENTS

ASTM A320 MECHANICAL / CHEMICAL REQUIREMENTS

Additional ASTM & SAE Fastener Standards

ASME B16.5 Stud Bolt – Flange Chart

 

ASTM A193/A193M is a specification from the Association of Standards & Materials that primarily govern industrial piping applications.  In the assembly of an industrial plant, many complex components are bolted together of which include parts such as valves, piping, & pressure vessels.  ASTM A193 defines the methodology to procure and certify externally threaded fasteners according to specific chemical and mechanical criteria.  It is standards such as this that allow industrial process applications to be safely engineered so they do not exceed the tensile strength of the fasteners that hold them together.

COMMON ASTM FASTENER SPECIFICATIONS FASTENER GRADES INCLUDE:

ASTM A193 Grade B7 Chromium Molybendum steel, normally AISI 4140, heat treated to 28-32Rockwell Hardness, 125,000 PSI tensile strength, 105, 000 PSI yield. It will hold it’s strength to 1000 degrees F.

ASTM A193 Grade B7M It has the same chemistry as B7. Physicals have max hardness of 235 Brinell or RC22. 100,000 PSI tensile and 80,000 PSI yield. Used in areas where H2S is present.

ASTM A193 Grade B16 Chromium, molybendum, Vanadium steel. It has the same physicals as B7. Added vanadium allows it to hold it’s strength to 1100 degrees Fahrenheit.

ASTM A193 Grade B8 18-8 Grade stainless, non magnetic, good corrosion resistance. 75,000 PSI tensile strength. Same material as AISI type 304 stainless steel.

ASTM A193 Grade B8M This is similar to B8 fasteners except with added Molybdenum. It has better corrosion resistance than B8. Hex Bolts, studs and other fasteners are common to the B8M spec.

ASTM A193 Grade B8 Class 2 Studs, bolts, and other fasteners found in this grade are considered the same as B8 except strain hardened. This is a cold working process which increases physical properties. 100,000-125,000 PSI Tensile Strength.

ASTM A193 Grade B8M Class 2 Same as B8M except strain hardened, 90,000-125,000PSI Tensile Strength.

ASTM A193 Grade BC 18-8 grade stainless with additional element of Columbium- same as type 347 type stainless steel.

ASTM A193 Grade B8T 18-8 grade of stainless with additional element of Titanium. Same as type 321 Stainless Steel.

ASTM A193 Grade B6 This has the same chemistry as AISI type 410 stainless steel, but it is heat treated. 110,000 PSI tensile strength.

ASTM A193 Grade B5 Fasteners under the B5 spec have the same chemistry as AISI type 501 SS but they are heat treated to 100,000 PSI tensile strength.

ASTM A320 Grade L7 Bolts, studs, and other fasteners under the L7 grade have the same chemical and physical properties as B7. Additional requirement that it meet a Charpy Test at 150 degrees F is needed. Such fasteners are commonly used for low temperature service.

ASTM A320 Grade L7M

ASTM A320 Grade B8

18-8 Grade stainless, non magnetic, good corrosion resistance. 75,000 PSI tensile strength. Same material as AISI type 304 stainless steel.

ASTM A320 Grade B8M This is similar to B8 fasteners except with added Molybdenum. It has better corrosion resistance than B8. Hex Bolts, studs and other fasteners are common to the B8M spec.

ASTM A320 Grade B8 Class 2 Studs, bolts, and other fasteners found in this grade are considered the same as B8 except strain hardened. This is a cold working process which increases physical properties. 100,000-125,000 PSI Tensile Strength.

ASTM A320 Grade B8M Class 2 Same as B8M except strain hardened, 90,000-125,000PSI Tensile Strength.

ASTM A354 Grade BC High strength bolts for normal atmospheric temperature. 125,000 tensile. Lacks alloying elements of B7.

ASTM A354 Grade BD These hex bolts are the same as BC except they have a higher strength.

ASTM A449 Similar to A354 except has Manganese added, 90,000 to 120,000 tensile strength depending on size.

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