Stainless Steel SUS429J1
JIS SUS429J1
SUS429J1 is a molybdenum-modified 429-type ferritic stainless developed for automotive exhaust service, where the Mo addition improves high-temperature oxidation and condensate corrosion resistance over standard 429.
Reference datasheet — SUS429J1 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
SUS429J1 tempers and conditions
SUS429J1 is supplied in one standard condition, 1/4H.
Supply forms, finishes and certifications
Ways SUS429J1 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
ANN-BAR | Annealed bar / wire rod | Supply form |
CD-BAR | Cold drawn bar | Supply form |
WELD-TUBE | Welded tube, bright annealed after welding | Supply form |
1D | 1D / HRAP | Surface finish |
2BDefault | Cold rolled, annealed, pickled, skin-passed | Surface finish |
BA | Bright annealed cold rolled sheet | Surface finish |
No.4 | Cold rolled, annealed, abrasive-belt polished | Surface finish |
What is SUS429J1?
SUS429J1 is a molybdenum-modified 429-type ferritic stainless developed for automotive exhaust service, where the Mo addition improves high-temperature oxidation and condensate corrosion resistance over standard 429. It is stocked as 2B, BA, No.4 and 1D sheet, 1/4H temper strip, annealed and cold-drawn bar, and welded tube for exhaust fabrication. Annealed sheet runs about 300 MPa yield, 480 MPa tensile, 30 % elongation and 155 HB (82 HRB), with service to roughly 815 °C. Formability (68) trails dedicated deep-drawing grades and HAZ grain growth limits heavy sections, so 436L or 430J1L are the usual alternatives for pressed shapes. SUS429J1 has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,425°C (2,597 °F). SUS429J1 has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 480 MPa (69.6 ksi) — weaker than 68% of stainless steel grades. Elongation at break is 30% and the elastic modulus is 200 GPa (29 Msi).
What is SUS429J1 used for?
- exhaust manifolds
- catalytic converter housings
- heat shields
- flex pipe components
Advantages
- Easy to machine — 55/100, better than 94% of stainless steel grades
- Conducts heat well — 25 W/m·K (14.4 BTU/hr·ft·°F), better than 93% of stainless steel grades
- High electrical conductivity — 2.9 % IACS, better than 87% of stainless steel grades
- High service temperature — 815°C (1,499 °F), better than 77% of stainless steel grades
- Forms and bends easily — 68/100, better than 75% of stainless steel grades
Limitations
- Needs corrosion protection — 48/100, worse than 80% of stainless steel grades
SUS429J1 properties
Typical room-temperature values; bars are the position among stainless steel grades.
Physical3
SUS429J1 has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,425°C (2,597 °F).
Mechanical14
SUS429J1 has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 480 MPa (69.6 ksi) — weaker than 68% of stainless steel grades. Elongation at break is 30% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
SUS429J1 is rated for continuous service to 815°C (1,499 °F). It conducts heat at 25 W/m·K (14.4 BTU/hr·ft·°F), better than 93% of stainless steel grades. Thermal expansion is 10.4 µm/m·K (5.78 µin/in·°F).
Electrical3
SUS429J1 conducts electricity at 2.9 % IACS, better than 87% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (48/100), worse than 80% of stainless steel grades.
Sustainability4
Producing a kilogram of SUS429J1 takes about 52 MJ of energy and emits 4.2 kg of CO₂ — less than 76% of stainless steel grades. Typical recycled content is 65%.
Manufacturability7
SUS429J1's machinability is good (55/100, better than 94% of stainless steel grades); weldability good (55/100); formability good (68/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the stainless steel family
Yield strength against density for every stainless steel grade FabDigit runs. SUS429J1 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with SUS429J1
Is SUS429J1 easy to machine?
Machines more freely than austenitic stainless (~55 % of 1212); use sharp positive-rake carbide, rigid setup and generous coolant to avoid built-up edge and work-hardened skin.
Can SUS429J1 be welded?
Weldable by GTAW/laser/HF-ERW with low heat input; HAZ grain growth and 475 °C embrittlement risk — use 430/309 or Nb-stabilised filler and avoid preheat above ~150 °C, post-weld anneal for best ductility.
Can SUS429J1 be formed, bent or molded?
Good deep-drawing and roll-forming behaviour with modest springback; watch ridging/roping in drawn panels and keep bend radius ≥1t transverse to rolling direction.
SUS429J1 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| CJIS G4305 max | ≤ 0.12 | 0.06 |
| Si | ≤ 1 | 0.5 |
| Mn | ≤ 1 | 0.6 |
| P | ≤ 0.04 | 0.03 |
| S | ≤ 0.03 | 0.01 |
| Niresidual/permitted | ≤ 0.6 | 0.25 |
| Cr | 15 – 17 | 16 |
| Cudeliberate addition distinguishing J1 from plain SUS429 | 0.3 – 0.8 | 0.5 |
| Monot specified by JIS; some mill variants add ~0.3–0.5 % Mo for exhaust-condensate corrosion resistance — confirm on mill certificate | — | |
| Fe | balance |
What surface finishes work on SUS429J1?
Passivate or electropolish after pickling to restore the Cr-rich film; not anodizable — PVD colouring, painting or brushed/BA mill finishes are the usual routes.
Surface treatments FabDigit runs on stainless steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Passivation
Organic Coating
Thermal Spray
How much does SUS429J1 cost?
SUS429J1 is a standard-cost stainless steel ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
SUS429J1 — frequently asked
What is SUS429J1 used for?
SUS429J1 is typically used for exhaust manifolds, catalytic converter housings, heat shields and flex pipe components. In short: mo-modified 429 for exhaust; 815 °C oxidation resistance; nickel-free exhaust stainless.
What is the yield strength of SUS429J1?
SUS429J1 has a typical yield strength of 300 MPa (43.5 ksi) and a tensile strength of 480 MPa (69.6 ksi) — weaker than 68% of stainless steel grades.
Is SUS429J1 easy to machine?
Reasonably — machinability is rated good (55/100, better than 94% of stainless steel grades). Machines more freely than austenitic stainless (~55 % of 1212); use sharp positive-rake carbide, rigid setup and generous coolant to avoid built-up edge and work-hardened skin.
Can SUS429J1 be welded?
Yes — weldability is rated good (55/100). Weldable by GTAW/laser/HF-ERW with low heat input; HAZ grain growth and 475 °C embrittlement risk — use 430/309 or Nb-stabilised filler and avoid preheat above ~150 °C, post-weld anneal for best ductility.
What surface finishes work on SUS429J1?
Passivate or electropolish after pickling to restore the Cr-rich film; not anodizable — PVD colouring, painting or brushed/BA mill finishes are the usual routes.
Can SUS429J1 be formed, bent or molded?
Good deep-drawing and roll-forming behaviour with modest springback; watch ridging/roping in drawn panels and keep bend radius ≥1t transverse to rolling direction.
What is the maximum service temperature of SUS429J1?
SUS429J1 is rated for continuous use to about 815°C (1,499 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does SUS429J1 cost?
SUS429J1 is a standard-cost stainless steel ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- JIS G4305 Cold-rolled stainless steel plate, sheet and strip — JSA (2021)
- JIS G4304 Hot-rolled stainless steel plate, sheet and strip — JSA (2021)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels, and High-Performance Alloys (ferritic stainless) — ASM International (1990)
- Machinery's Handbook — machinability ratings for stainless steels — Industrial Press (2020)
- Ferritic stainless steels for automotive exhaust systems — Nippon Steel Stainless / JFE (2020)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.