Every heat is analysed at the steel mill and the result goes on the certificate. A product analysis checks the finished part, and the bolting specifications list how far it may stray from each limit: for B7 it is 0.02% on carbon, so studs from a heat made to 0.38 to 0.48% carbon may read 0.36 to 0.50%. That tolerance applies only to a product analysis, never to the heat analysis.
Some elements decide the grade at levels a handheld analyser cannot see. L1 bolting is a boron steel with 0.001 to 0.003% boron (ASTM A320), low carbon is what makes a stainless steel an L grade, and duplex 2205 carries 0.14 to 0.20% nitrogen. Chemistry does not show heat treatment, though: B7 and B7M share one chemistry table and differ in tempering and hardness.
Read the full chemical analysis page →
model dataHeat analysis of every heat, the mid-radius product-analysis sample and the rule that product tolerances never apply to the heat analysis from ASTM A962 and A193; B7 limits and product-analysis variations from ASTM A193 Table 1. Spark emission to ASTM E415 (carbon and low-alloy steel) and E1086 (austenitic stainless, flat face at least 13 mm across); carbon and sulfur by combustion and infrared absorption, nitrogen and oxygen by inert-gas fusion, to ASTM E1019. The handheld XRF limit from an analyser maker's published guidance. The stud is drawn as a 1 in. × 6 in. B7 stud with 1-8 UNC threads; the cut-off saw, grinder, spectrometer and combustion analyser are generic, and every reading is for illustration. Cutting, grinding, sparking and burning are time-lapsed, and the light is drawn as coloured rays.
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