ASTM A182

USED FOR:

Governs forged or rolled alloy steel and stainless steel piping components: flanges, fittings, valves, and similar pressure-containing parts  for high-temperature and corrosion-resistant service.

This is primarily a forging material specification (like A105) covering alloy and stainless steels. It also permits certain components to be machined from rolled or forged bar meeting the requirements of ASTM A182, provided the product complies with all specification requirements.

RELATED STANDARDS:

• Sibling specs: ASTM A105 covers plain carbon steel forgings for ambient/moderate temperature service where alloy or corrosion resistance isn’t needed; ASTM A350 covers carbon/low-alloy forgings for low-temperature service with mandatory impact testing; A182 sits above both in temperature/corrosion capability, covering chrome-moly grades for elevated temperature and austenitic/duplex stainless grades for corrosion resistance and cryogenic service alike.
• Design code that invokes it: ASME B16.5 and B16.47 reference A182 as a listed flange material, and ASME B31.3/B31.1 pull allowable stresses for A182 grades from ASME Section II Part D, particularly for creep-range design in the F-series chrome-moly grades and corrosion/temperature-driven design in the stainless F-grades.
• Dimensional standard that pairs with it: ASME B16.5/B16.47 for flanges and B16.11 for forged socket-weld/threaded fittings define the geometry, A182 governs material only.

GRADE / TYPE RANGE:
A182 covers two broad families. The ferritic/martensitic chrome-moly grades (F1, F5, F9, F11, F22, F91, etc.) progressively increase chromium and molybdenum content, improving high-temperature creep strength and hydrogen attack resistance, with F91 (modified 9Cr-1Mo) representing the high end, requiring tight heat treatment control (normalize and temper) to achieve its combination of high strength and reasonable ductility.

The austenitic stainless grades (F304, F304L, F316, F316L, F321, F347, etc.) are chromium-nickel alloys where the “L” (low carbon) variants trade a modest strength reduction for resistance to sensitization/intergranular corrosion after welding, and the stabilized grades (321, 347) use titanium or niobium additions for the same purpose at higher service temperatures.

Duplex and super-duplex grades (such as F51, F53 and F55) are also covered, offering higher strength and superior resistance to chloride stress corrosion cracking than standard austenitic stainless steels. Solution annealing is critical for these grades, while PWHT is generally not applied unless specifically qualified for the material and service.

Grade selection is driven by a combination of design temperature (creep range vs. corrosion resistance), process fluid corrosivity (chlorides, sour species), and whether post-weld sensitization or SCC resistance matters for the service.

DESCRIPTION:
A182 covers forged (and some rolled bar) alloy and stainless steel components , flanges, fittings, valves, produced to standard dimensional shapes, distinguished from A105 primarily by its much broader chemistry range and from A403 (wrought stainless fittings, typically formed from pipe/plate) by its forging-based product form.

The standard specifies chemical composition ranges for each F-grade, mechanical property requirements (tensile, yield, elongation, and hardness where relevant), and heat treatment requirements that vary significantly by grade family, Heat treatment requirements vary by grade. Ferritic and martensitic grades are supplied in the heat-treated condition specified for the individual grade (such as normalized and tempered where required), while austenitic stainless steels are solution annealed in accordance with the grade requirements.

It addresses mandatory tension testing, and for certain grades, additional requirements like intergranular corrosion testing (for stabilized/low-carbon stainless grades) or impact testing depending on grade and edition. Marking requirements identify grade, heat, and manufacturer for traceability, which becomes particularly important on jobs mixing multiple similar-looking stainless grades (e.g., 316 vs. 316L) where a documentation mix-up can have real corrosion consequences downstream.

TYPICAL INDUSTRY USE:
Widely specified in refining, petrochemical, and power generation for elevated-temperature process piping (chrome-moly grades) and in chemical processing, offshore, and corrosive-service piping (stainless and duplex grades) wherever A105 carbon steel is inadequate for temperature or corrosion reasons.

IMPORTANT NOTES:

• We catched some project-cases where F316 is specified/supplied when F316L was actually required (or vice versa),  the strength difference is not so much on paper but the corrosion/sensitization performance difference after welding is significant it is a point we scrutinize closely at MTR review, especially on welded assemblies requiring PWHT.

• Supplementary requirements (S-series, varying by grade) can add impact testing, intergranular corrosion testing (particularly relevant for stabilized grades in sensitizing service), or additional NDE, we recommend confirming exactly which supplements the project spec require rather than assuming standard testing covers them.

• NACE MR0175/ISO 15156 compliance is a major consideration for several A182 grades in sour service, F22 and F91 need hardness control (commonly capped around 22 HRC, though this varies by grade/condition) and F91 in particular requires tight PWHT control to meet sour hardness limits without under-tempering; duplex grades (F51/F53) have their own sour-service qualification nuances around ferrite content and hardness that we always verify against the specific NACE/ISO requirements invoked.

• F91 forgings deserve special procurement attention: heat treatment window, hardness, and impact toughness are all tightly interlinked, and we’ve seen mills struggle to hit all three, we recommend requesting full heat treatment records and hardness survey data on F91 flanges/fittings before acceptance.