Stainless Steel – Grade 434 (UNS S43400)

Topics Covered

Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Other Designations
Fabrication and Heat Treatment
Machinability
Forming
Welding
Forging
Annealing
Hardening
Applications

Introduction

Stainless steels are high-alloy steels. They have high corrosion resistance due to high chromium content of about 4-30%. They are classified in to three types such as ferritic, austenitic, and martensitic steels based on their crystalline structure.

Grade 434 stainless steel contains added molybdenum to increase its corrosion resistance. It is has performance and chemistry similar to that of 430 stainless steel.

Chemical Composition

The following table shows the chemical composition of grade 434 stainless steel.

Element Content (%)
Iron, Fe 81
Chromium, Cr 16
Molybdenum, Mo 1
Silicon, Si 1
Manganese, Mn 1
Carbon, C 0.12
Phosphorous, P 0.040
Sulfur, S 0.030

Physical Properties

The physical properties of grade 434 stainless steel are given in the following table.

Properties Metric Imperial
Density 7.80 cm³ 0.282 lb/in³
Melting point 1510°C 2750°F

Mechanical Properties

The following table outlines the mechanical properties of annealed grade 434 stainless steel.

Properties Metric Imperial
Tensile strength 538 MPa 78000 psi
Yield strength (@ strain 0.200%) 441 MPa 64000 psi
Elastic modulus 200 GPa 29008 ksi
Poisson's ratio 0.27-0.30 0.27-0.30
Elongation at break (in 50 mm) 32% 32%
Hardness, Rockwell B (converted from Brinell hardness) 89 89

Thermal Properties

The thermal properties of grade 434 stainless steel are displayed in the following table.

Properties Metric Imperial
Thermal expansion co-efficient (@ 0-100°C/32-212°F) 10.4 µm/m°C 5.78 µin/in°F
Thermal conductivity (@ 100°C/212°F) 26.1 W/mK 181 BTU in/hr.ft².°F

Other Designations

Other designations that are equivalent to grade 434 stainless steel include:

  • DIN 1.4113
  • AFNOR Z 8 CD 17.01
  • UNI X 8 CrMo 17
  • JIS SUS 434
  • SS 2325
  • B.S. 434 S 19
  • ASTM A65i
  • SAE 51434
  • SAE J405 (51434)

Fabrication and Heat Treatment

Machinability

Grade 434 stainless steel can be machined using all standard procedures.

Forming

Blanking, shearing, and deep drawing operations can be successfully performed due to its high ductility.

Welding

Grade 434 stainless steel can be welded using common techniques. After welding, it should be thoroughly cleaned to increase corrosion resistance property.

Forging

Grade 434 stainless steel can be forged at 1094 -1149°C (2000-2100°F) after thorough soaking.

Annealing

Grade 434 stainless steel is annealed by soaking at 788 - 872°C (1450-1600°F) followed by cooling in air.

Hardening

Grade 434 stainless steel does not react to heat treatment.

Applications

Grade 434 stainless steel is used in automotive trim applications and other exterior environments.

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