XM-29 (UNS S24000) Stainless Steel Reinforcement Bars
When infrastructure demands uncompromising corrosion resistance, the choice of reinforcement defines its service life. FUSHUN METAL (Hunan Fushun Metal Co., Ltd.), a global manufacturer and exporter of specialty steels, produces XM-29 (UNS S24000) deformed and plain stainless steel reinforcement bars in full conformance with ASTM A955/A955M — the standard specification for deformed and plain stainless steel bars for concrete reinforcement. Our manufacturing disciplines, compliant with ASTM, EN, DIN, and JIS standards, deliver products engineered for aggressive environments where conventional carbon steel fails.
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Chemical Composition
The corrosion resistance and mechanical performance of XM-29 begin with its precisely controlled chemistry. We perform a heat analysis from test samples taken during the pouring or casting of every heat. The composition conforms strictly to the requirements of ASTM A955/A955M Table 2 for UNS S24000.
| Element | Composition % |
|---|---|
| Carbon (C) | 0.08 max. |
| Manganese (Mn) | 11.50 – 14.50 |
| Phosphorus (P) | 0.060 max. |
| Sulfur (S) | 0.030 max. |
| Silicon (Si) | 1.00 max. |
| Chromium (Cr) | 17.00 – 19.00 |
| Nickel (Ni) | 2.25 – 3.75 |
| Nitrogen (N) | 0.20 – 0.40 |
This high-manganese, nitrogen-strengthened austenitic grade has found the most use in North America. It delivers an optimal combination of strength, ductility, and chloride-induced corrosion resistance at a cost advantage over high-nickel alternatives. When specified, a product analysis can be performed and will conform to the analysis tolerances of ASTM A484/A484M.
Heat Treatment Condition
The mechanical properties of XM-29 reinforcement bars are directly governed by the heat treatment condition at the time of manufacture. FUSHUN METAL supplies bars in the following conditions, as defined in ASTM A276 and referenced by ASTM A955/A955M:
- Annealed (A)
- Hot Rolled (HR)
- Strain Hardened (B)
The selection of heat treatment condition is an essential ordering decision, as it fundamentally influences strength and ductility. Any further heat treatment applied after delivery may alter these properties. The standard advises that no re-treatment should be imposed without retesting to the requirements of this specification.
Size
FUSHUN METAL manufactures XM-29 deformed bars across the full range of standard bar designation numbers listed in ASTM A955/A955M Table 1. The nominal dimensions of a deformed bar are equivalent to those of a round bar having the same weight per foot as the deformed bar.
| Bar Designation No. | Nominal Diameter, in. [mm] | Nominal Weight, lb/ft [kg/m] (300 Series) |
|---|---|---|
| 3 [10] | 0.375 [9.5] | 0.378 [0.562] |
| 4 [13] | 0.500 [12.7] | 0.686 [1.021] |
| 5 [16] | 0.625 [15.9] | 1.058 [1.575] |
| 6 [19] | 0.750 [19.1] | 1.511 [2.248] |
| 7 [22] | 0.875 [22.2] | 2.059 [3.064] |
| 8 [25] | 1.000 [25.4] | 2.713 [4.037] |
| 9 [29] | 1.128 [28.7] | 3.341 [5.106] |
| 10 [32] | 1.270 [32.3] | 4.358 [6.484] |
| 11 [36] | 1.410 [35.8] | 5.352 [7.964] |
| 14 [43] | 1.693 [43.0] | 7.72 [11.49] |
| 18 [57] | 2.257 [57.3] | 13.72 [20.43] |
Plain rounds in diameters up to and including 2 in. [50.8 mm] are also available for use as dowels, spirals, and structural ties. Bars are furnished in standard or custom-cut lengths as required by the project.
Grade (Strength Level)
XM-29 bars are produced in three minimum yield strength grades, as prescribed in ASTM A955/A955M. The tensile properties for each grade are verified on specimens representing the full section of the bar as rolled, with unit stress calculated on the nominal bar area.
| Grade | Tensile Strength, min | Yield Strength, min |
|---|---|---|
| Grade 40 [300] | 70,000 psi [500 MPa] | 40,000 psi [300 MPa] |
| Grade 60 [420] | 90,000 psi [620 MPa] | 60,000 psi [420 MPa] |
| Grade 75 [520] | 100,000 psi [690 MPa] | 75,000 psi [520 MPa] |
Yield strength is determined at 0.35% strain using the autographic diagram method or an extensometer, in accordance with ASTM A370. Elongation requirements are grade- and size-dependent, as specified in ASTM A955/A955M Table 3. The grade shall be clearly specified at the time of order.
Packaging
FUSHUN METAL ensures that all XM-29 reinforcement bars are properly separated and tagged with the manufacturer's heat or test identification number when loaded for mill shipment. Each bundle is tagged with the following information:
- Stainless steel alloy (XM-29 / UNS S24000)
- Heat treatment condition
- Grade (minimum strength level)
- Supplementary requirement status (S1, if applicable)
For orders where packaging is specified in the purchase order, procedures conform to ASTM A700. For U.S. Government procurement, packaging complies with MIL-STD-163, and marking for shipment conforms to Fed. Std. No. 123 for civil agencies or MIL-STD-129 for military agencies. Every deformed bar is legibly marked on one side with the manufacturer's mill designation and the bar size designation. Plain rounds do not require rolled-on symbols; all identifying information is provided on the bundle tag.
Inspection
The purchaser's inspector shall have free entry, at all times while work on the contract is being performed, to all parts of the manufacturer's works that concern the manufacture of the material ordered. FUSHUN METAL provides access to all reasonable facilities to verify that material is being furnished in accordance with ASTM A955/A955M. All tests and inspection are conducted at the place of manufacture prior to shipment and are performed so as not to interfere unnecessarily with the operation of the works.
Test
For every heat, bar size, and heat treatment condition, FUSHUN METAL performs the following tests as a minimum:
- One tension test — full section of the bar as rolled, evaluated against the tensile requirements of the specified grade.
- One bend test — full section of the bar as rolled, bent around a pin of specified diameter without cracking on the outside radius. Bend test requirements conform to ASTM A955/A955M Table 4.
- One set of dimensional property tests — including bar weight, and measurement of deformation spacing, height, and gap, all verified against the requirements of ASTM A955/A955M Table 1.
For deformation measurements, the average spacing is determined from a minimum of ten spaces. The measured weight of any deformed bar shall be at least 94% of the applicable weight per unit prescribed in Table 1. If a test specimen fails for mechanical reasons, a replacement specimen is permitted. For failures meeting specified retest conditions, two additional random specimens are tested and must fully meet the specification requirements. When Supplementary Requirement S1 is invoked for controlled magnetic permeability, testing is performed in accordance with ASTM A342, with specific permeability limits agreed between manufacturer and purchaser.
Report
FUSHUN METAL provides a Material Test Report, Certificate of Inspection, or similar document for every order. The report is issued on a per-heat or per-lot basis and includes:
- Stainless steel type and name (XM-29 / UNS S24000)
- Chemical composition (heat analysis and product analysis, if performed)
- Heat treatment condition
- Bar size
- Tensile properties (tensile strength, yield strength, elongation)
- Bend test results
- Corrosion test results (if specified)
- Magnetic permeability results (if Supplementary Requirement S1 is invoked)
Documents transmitted via electronic data interchange (EDI) carry the same validity as printed counterparts. The content of any EDI-transmitted document meets all requirements of ASTM A955/A955M.
Frequently Asked Questions
What makes XM-29 (UNS S24000) a good choice for concrete reinforcement in corrosive environments?
XM-29 is a nitrogen-strengthened austenitic stainless steel with high chromium and manganese. It resists chloride-induced corrosion better than carbon steel and provides higher strength than 304 stainless at a lower nickel cost, ideal for marine or deicing salt exposure.
How do I select the correct heat treatment condition and grade for XM-29 bars?
Select the heat treatment condition (Annealed, Hot Rolled, Strain Hardened) that suits your fabrication state, then choose Grade 40, 60, or 75 based on required minimum yield strength. Our engineers help match properties per ASTM A955.
What documentation and traceability does FUSHUN METAL provide with each shipment?
Each shipment includes a Material Test Report with chemical analysis, tensile and bend results, and heat treatment details. Bundles are tagged, and deformed bars carry mill markings and size designation for full melt-to-site traceability.
Can I order XM-29 bars with controlled magnetic permeability in addition to corrosion resistance?
Yes. Invoke Supplementary Requirement S1. We manufacture and test to ASTM A342 with agreed permeability limits, ensuring non-magnetic properties for MRI or sensitive electronic applications.
Get XM-29 Reinforcement Bars for Your Project
FUSHUN METAL (Hunan Fushun Metal Co., Ltd.) is a trusted global manufacturer of alloy steel, nickel-based alloys, stainless steel, and tool steel. Our products serve demanding industries worldwide, backed by full compliance with international standards including ASTM, EN, DIN, and JIS. For inquiries and technical support on XM-29 (UNS S24000) reinforcement bars, Request a Quote or visit our website.
