MF FASTENER INDUSTRIES LLC
Manufacturer of anchor bolts, studs & plate washers · Importer & stockist of fasteners
Technical datasheet
ASTM A193 / A193M — Grade B7 alloy steel stud bolt
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Reference only — for design, verification or
contractual purposes refer to the current issue of the original standard.
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A193 B7
Dimensional datasheet
ASTM A193 Grade B7Chrome-moly alloy steel stud bolt, quenched and tempered, for high-temperature and high-pressure flanged joints. The default bolting specification across process piping, refineries and pressure vessels. d nominal thread diameterP thread pitchL stud length
DimensionsinchesImperial sizes. UNC to 1 inch, 8 UN above — flange bolting is 8 UN by convention, not UNC, above 1 inch. Studs are supplied cut to length with chamfered ends and two nuts.
Strength falls with diameter125 ksi tensile and 105 ksi yield apply up to and including 2-1/2 inch. Above that the figures drop: 115 / 95 ksi to 4 inch, and 100 / 75 ksi from 4 to 7 inch. Section size limits how deeply the quench hardens. Check the figure for the diameter you are designing to rather than assuming 125 ksi throughout. B7, B7M and B16 are different productsB7 — standard, 125 ksi. B7M — tempered softer to 235 HBW max for sour service under NACE MR0175, at 100 ksi tensile. B16 — chrome-moly-vanadium, for service above the B7 limit. B7M is not a stronger B7 and B7 is not acceptable where MR0175 applies. Supply what the piping specification names. B7 is not A320 L7The two are commonly the same base alloy and look identical. A320 L7 carries a Charpy impact test at −101 °C; B7 does not. For low-temperature service the specification is A320. Substituting B7 removes the toughness verification the designer relied on. Metric — A193MASTM A193M
Metric flange bolting is less common in process piping than imperial; most ASME flanges are drilled to imperial bolt circles. Grades and serviceA193 / A194 pairing
The nut grade is part of the specification, not an afterthought. A 2H nut on a B7M stud defeats the sour-service requirement. At a glance
SupplyStud bolts are manufactured at our own plant — cut to length, threaded, chamfered and coated to your specification, with nuts supplied to match. Bar stock is sourced from certified mills with test results traceable to the heat number. Finish
TestingDimensional and thread inspection is carried out in our own plant on calibrated instruments. Tensile, hardness and chemical testing is carried out by independent UAE-accredited laboratories. Reference onlyThis datasheet is published for reference. Dimensions and property values are reproduced in good faith from published standards, but for design, verification or contractual purposes always refer to the current issue of the original standard. If a figure here conflicts with the standard, the standard governs. Need a quotation?Send the size, length, grade, nut grade, coating and quantity. If the joint is sour service or low temperature, say so — the grade changes. |