# Half-Hard 304 Stainless Steel

Half-hard AISI 304 is AISI 304 stainless steel in the half-hard temper. It has the highest strength and lowest ductility compared to the other variants of AISI 304 stainless steel. The graph bars on the material properties cards below compare half-hard AISI 304 to: wrought austenitic stainless steels (top), all iron alloys (middle), and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.

## Mechanical Properties

Brinell Hardness

360

Elastic (Young's, Tensile) Modulus

200 *GPa* 29 *x 10 ^{6} psi*

Elongation at Break

8.0 *%*

Fatigue Strength

440 *MPa* 63 *x 10 ^{3} psi*

Poisson's Ratio

0.28

Shear Modulus

77 *GPa* 11 *x 10 ^{6} psi*

Shear Strength

690 *MPa* 100 *x 10 ^{3} psi*

Tensile Strength: Ultimate (UTS)

1180 *MPa* 170 *x 10 ^{3} psi*

Tensile Strength: Yield (Proof)

860 *MPa* 120 *x 10 ^{3} psi*

## Thermal Properties

Latent Heat of Fusion

290 *J/g*

Maximum Temperature: Corrosion

420 *°C* 790 *°F*

Maximum Temperature: Mechanical

710 *°C* 1300 *°F*

Melting Completion (Liquidus)

1450 *°C* 2640 *°F*

Melting Onset (Solidus)

1400 *°C* 2550 *°F*

Specific Heat Capacity

480 *J/kg-K* 0.11 *BTU/lb-°F*

Thermal Conductivity

16 *W/m-K* 9.2 *BTU/h-ft-°F*

Thermal Expansion

17 *µm/m-K*

## Electrical Properties

Electrical Conductivity: Equal Volume

2.4 *% IACS*

Electrical Conductivity: Equal Weight (Specific)

2.7 *% IACS*

## Otherwise Unclassified Properties

Base Metal Price

15 *% relative*

Calomel Potential

-80 *mV*

Density

7.8 *g/cm ^{3}* 490

*lb/ft*

^{3}Embodied Carbon

3.0 *kg CO _{2}/kg material*

Embodied Energy

43 *MJ/kg* 18 *x 10 ^{3} BTU/lb*

Embodied Water

150 *L/kg* 17 *gal/lb*

## Common Calculations

PREN (Pitting Resistance)

20

Resilience: Ultimate (Unit Rupture Work)

86 *MJ/m ^{3}*

Resilience: Unit (Modulus of Resilience)

1870 *kJ/m ^{3}*

Stiffness to Weight: Axial

14 *points*

Stiffness to Weight: Bending

25 *points*

Strength to Weight: Axial

42 *points*

Strength to Weight: Bending

32 *points*

Thermal Diffusivity

4.2 *mm ^{2}/s*

Thermal Shock Resistance

25 *points*

## Alloy Composition

Fe | 66.5 to 74 | |

Cr | 18 to 20 | |

Ni | 8.0 to 10.5 | |

Mn | 0 to 2.0 | |

Si | 0 to 0.75 | |

N | 0 to 0.1 | |

C | 0 to 0.080 | |

P | 0 to 0.045 | |

S | 0 to 0.030 |

All values are % weight. Ranges represent what is permitted under applicable standards.

## Followup Questions

## Further Reading

ASTM A666: Standard Specification for Annealed or Cold-Worked Austenitic Stainless Steel Sheet, Strip, Plate, and Flat Bar

ASTM A182: Standard Specification for Forged or Rolled Alloy and Stainless Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High-Temperature Service

ASTM A276: Standard Specification for Stainless Steel Bars and Shapes

Creep-Resistant Steels, Fujio Abe et al. (editors), 2008

Advanced Materials in Automotive Engineering, Jason Rowe (editor), 2012

ASTM A959: Standard Guide for Specifying Harmonized Standard Grade Compositions for Wrought Stainless Steels

Corrosion of Austenitic Stainless Steels: Mechanism, Mitigation and Monitoring, H. S. Khatak and B. Raj (editors), 2002

Pressure Vessels: External Pressure Technology, 2nd ed., Carl T. F. Ross, 2011

Austenitic Stainless Steels: Microstructure and Mechanical Properties, P. Marshall, 1984

ASM Specialty Handbook: Stainless Steels, J. R. Davis (editor), 1994