15B21H Boron Alloy High Carbon Steel Bolting Products
15B21H Boron Alloy High Carbon Steel is listed in the HIGH CARBON STEEL material family. The reference data below should be checked against the governing product specification, product form and delivery condition before selection or certification.
The reference chemistry table for 15B21H Boron Alloy High Carbon Steel lists Carbon (C): 0.18 – 0.23%; Silicon (Si): 0.15 – 0.35%; Manganese (Mn): 0.70 – 0.90%; Phosphorus (P): 0.035% Max. Confirm exact limits and analysis tolerances against the governing standard and product form.
The mechanical-property table for 15B21H Boron Alloy High Carbon Steel lists Tensile Strength: 650 – 850 MPa; Yield Strength: 400 – 650 MPa; Elongation: 14 – 24 %; Hardness: 180 – 240 HB. These are reference entries; supplied condition, dimensions, test method and governing specification control the requirements, and the figures are not design allowables.
No one-to-one Werkstoff number was verified for 15B21H Boron Alloy High Carbon Steel in the cross-reference sources checked for this update. Confirm any proposed EN alternative against the governing specification.
View Technical Information →Standard identification and material designation information for 15B21H Boron Alloy High Carbon Steel.
The reference chemistry table lists Carbon (C): 0.18 – 0.23%; Silicon (Si): 0.15 – 0.35%; Manganese (Mn): 0.70 – 0.90%; Phosphorus (P): 0.035% Max. Confirm the governing standard, product analysis tolerances and product form before ordering.
| Element | Symbol | Composition |
|---|---|---|
| Carbon | C | 0.18 – 0.23% |
| Silicon | Si | 0.15 – 0.35% |
| Manganese | Mn | 0.70 – 0.90% |
| Phosphorus | P | 0.035% Max |
| Sulfur | S | 0.040% Max |
| Boron | B | 0.0005 – 0.0030% |
| Chromium | Cr | 0.20% Max |
| Nickel | Ni | 0.40% Max |
| Molybdenum | Mo | 0.15% Max |
| Iron | Fe | Balance |
The table reports Tensile Strength: 650 – 850 MPa; Yield Strength: 400 – 650 MPa; Elongation: 14 – 24 %; Hardness: 180 – 240 HB as reference data for 15B21H Boron Alloy High Carbon Steel. Actual requirements depend on condition, dimensions, test method and specification; these values are not design allowables.
| Property | Value | Unit |
|---|---|---|
| Tensile Strength | 650 – 850 | MPa |
| Yield Strength | 400 – 650 | MPa |
| Elongation | 14 – 24 | % |
| Hardness | 180 – 240 | HB |
15B21H Boron Alloy High Carbon Steel combines a relatively high carbon level with heat-treatment capability. The selected grade is used where strength, hardness, wear performance or hardenability are important.
Controlled boron additions can significantly improve hardenability when metallurgical conditions are suitable.
The 15B family is commonly associated with heat-treated fasteners and automotive components.
Carbon content supports useful strength and hardness after suitable heat treatment.
The grade family is used where controlled hardenability can help achieve repeatable properties.
15B21H Boron Alloy High Carbon Steel is selected for applications where strength, hardness, wear resistance or controlled hardenability are important.
Used for cold-headed and carburizing fastener applications where hardenability is required.
Suitable for selected automotive pins, bolts and formed components.
Used in selected heat-treated pins and small mechanical parts.
Selected for parts requiring predictable boron-assisted hardenability.
Specify 15B21H together with the required heat-treatment condition and product form.
Boron effectiveness depends on processing and metallurgy, so the required hardenability should be verified on the actual heat.
For critical fasteners or automotive parts, use the governing SAE/AISI specification and certified chemistry and mechanical test results.
No one-to-one Werkstoff number was verified for 15B21H Boron Alloy High Carbon Steel in the cross-reference sources checked for this update, so this page does not assign a number. Confirm any proposed EN alternative against the applicable product standard and supplier certificate before substitution.
Our engineering team can help you select suitable materials based on operating temperature, pressure and service conditions.