ASTM A193/A193M-26 composition requirements and conditions
Standard reference requirements compiled from ASTM A193/A193M-26. Raw-material composition and the Class, heat treatment and performance conditions of finished components require separate confirmation; these are not actual supply or measured heat results.
Composition: Table 1, physical page 3; mass fraction wt%. Values are upper limits unless ranges, minimum values or conditional requirements are stated separately.
| Element | Requirement |
|---|---|
| C | 0.38—0.48 |
| Mn | 0.75—1.00 |
| P | ≤ 0.035 |
| S | ≤ 0.040 |
| Si | 0.15—0.35 |
| Cr | 0.80—1.10 |
| Ni | Not specified (must not be assumed 0) |
| Mo | 0.15—0.25 |
| Cu | Not specified (must not be assumed 0) |
| Nb | Not specified (must not be assumed 0) |
| Ti | Not specified (must not be assumed 0) |
| V | Not specified (must not be assumed 0) |
| Al | Not specified (must not be assumed 0) |
| N | Not specified (must not be assumed 0) |
Table 1, Footnote C: The similar steel types listed are examples only and do not establish material equivalence or substitution approval. Specific composition and ordering conditions require separate confirmation.
Product-analysis tolerances are separate from the base composition ranges; intentional additions of Bi, Se, Te and Pb are prohibited.
Product-analysis tolerances (wt%, Table 1; must not be added directly to the base composition ranges)
| Element | Deviation |
|---|---|
| C | 0.02 |
| Mn | 0.04 |
| P | 0.005 |
| S | 0.005 |
| Si | 0.02 |
| Cr | 0.05 |
| Ni | Not listed in the original table (do not enter 0) |
| Mo | 0.02 |
| Cu | Not listed in the original table (do not enter 0) |
| Nb | Not listed in the original table (do not enter 0) |
| Ti | Not listed in the original table (do not enter 0) |
| V | Not listed in the original table (do not enter 0) |
| Al | Not listed in the original table (do not enter 0) |
| N | Not listed in the original table (do not enter 0) |
Product-analysis tolerances are separate from the tabulated requirements. For the same element in the same heat, deviations must not occur both above and below the range. Unless otherwise stated, maximum values allow upward deviations only, ranges allow upward or downward deviations, and minimum values allow downward deviations only. Tolerances must not be added to the tabulated ranges in advance.
Customary-unit properties (Table 2)
Under 1.6, customary units apply unless the order or contract specifies the metric M edition. Under 1.7, the two unit systems are used independently and must not be mixed or combined through conversion. Properties are room-temperature requirements after the corresponding heat treatment; the specific Class, product form, specimen and order require separate confirmation.
| Grade | Class | Diameter condition | Heat treatment / minimum tempering temperature | Rm≥ ksi | Rp0.2≥ ksi | A4D≥ % | Z≥ % | Maximum hardness | Footnote | Physical page |
|---|---|---|---|---|---|---|---|---|---|---|
| B7M | Ferritic grades | Up to 4 in | Minimum tempering temperature 1150 °F | 100 | 80 | 18 | 50 | 235 HBW or 99 HRB | A | 6 |
| B7M | Ferritic grades | Over 4 up to 7 in | Minimum tempering temperature 1150 °F | 100 | 75 | 18 | 50 | 235 HBW or 99 HRB | A | 6 |
- A: To meet the tensile requirements, B7M must have a Brinell hardness greater than 200 HBW (93 HRB), while retaining the tabulated upper limit.
Metric properties (Table 3)
Under 1.6, customary units apply unless the order or contract specifies the metric M edition. Under 1.7, the two unit systems are used independently and must not be mixed or combined through conversion. Properties are room-temperature requirements after the corresponding heat treatment; the specific Class, product form, specimen and order require separate confirmation.
| Grade | Class | Diameter condition | Heat treatment / minimum tempering temperature | Rm≥ MPa | Rp0.2≥ MPa | A4D≥ % | Z≥ % | Maximum hardness | Footnote | Physical page |
|---|---|---|---|---|---|---|---|---|---|---|
| B7M | Ferritic grades | Up to M100 | Minimum tempering temperature 621 °C | 690 | 550 | 18 | 50 | 235 HBW or 99 HRB | A | 7 |
| B7M | Ferritic grades | Over M100 up to M180 | Minimum tempering temperature 621 °C | 690 | 515 | 18 | 50 | 235 HBW or 99 HRB | A | 7 |
- A: To meet the tensile requirements, B7M must have a Brinell hardness greater than 200 HBW (93 HRB), while retaining the tabulated upper limit.
Product form, heat treatment and inspection limitations
- 9.1.1: Table 2/3 tensile requirements apply at room temperature after heat treatment. Strain-hardened stainless steel components (Class 2/2B/2C) are tested full-size after strain hardening. Where equipment capacity is insufficient, components over 1.500 in. in diameter may be tested using machined specimens. If full-size and specimen results conflict, the full-size results govern. The original dimensional condition is stated only in customary units; no metric endpoint is invented.
- 9.1.2, 12.1.3: Applicable headed components also require full-size wedge-load testing. The minimum wedge tensile load is calculated from the specified tensile strength and thread stress area. Units: ksi×in² gives kip (×1000 gives lbf); MPa×mm² gives N (÷1000 gives kN). Unnormalized products must not be labelled directly as lbf or kN. Verify the stress area under A962/A962M. Material-specimen properties do not replace applicable finished-component testing; confirm the applicable head type, size and length under 12.1.3.
- 9.2.1: Hardness requirements follow Table 2/3, with testing under A962/A962M or F606/F606M. A tabulated maximum hardness does not establish that finished-product hardness testing has been completed.
- 9.2.2: B7M hardness has both an upper limit of 235 HBW or 99 HRB and a lower limit of 200 HBW or 93 HRB. Each stud or bolt must meet the hardness requirements. After conformity is established by the specified indentation sampling, 100% electromagnetic testing under E566 may be used, followed by indentation sampling of at least 100 pieces per heat per lot. Any out-of-limit sample causes lot rejection and handling under the original provisions. HBW and HRB are alternative test scales in the original, not conversions by this tool.
- 6.1.2, 6.1.3: Water quenching is prohibited when ferritic grades are heat treated after heading or thread forming. Except for the specified B6X exception, material cold drawn for dimensional control after heat treatment must be stress relieved after cold drawing, at a temperature no lower than the original tempering temperature minus 55°C, and mechanically tested after stress relief.
- 6.1.5: B7/B7M use liquid-medium quenching and tempering. The heating method and special requirements for B7 require separate confirmation under the clauses and order.
- 6.1.6, 6.1.6.1: B7M requires final stress relief after all machining, cutting and forming, at a minimum temperature equal to the original tempering temperature minus 28°C; tempering may be used instead. If the original tempering was by induction above 705°C and subsequent stress relief uses a conventional furnace, the minimum stress-relief temperature is 649°C. This condition must not be presented as a fixed 649°C requirement for all B7M.
Items on hold
- The original wording states exceeding 3½ in.[90 mm] while also indicating inclusion, creating a boundary-wording conflict. Retain the original and suspend automatic determination at the 90 mm endpoint. C may reach 0.50% for larger sizes. For B7M, the minimum C may be 0.28% where the corresponding section meets the tensile requirements, and 4130/4130H are permitted; this must not generally change the B7 minimum.
Contact: website@chqwire.net. This information is for technical material-selection reference only; it is not a quotation, contractual guarantee or heat-specific quality certificate. The applicable standard, order and material certificate govern.