Add molybdenum to a stabilized ferritic and you get grade 436: the corrosion and heat resistance an exhaust system actually needs where road salt and condensate attack the metal from both sides. It keeps 439's weldability while the molybdenum lifts pitting resistance, which is why 436 lands in the hot end of automotive exhaust and in appliance trim exposed to weather. USA Piping Solution supplies SS 436 ERW pipes and tubes in this molybdenum-bearing stabilized ferritic grade. For exhaust service without the molybdenum premium, our SS 439 ERW page covers the standard stabilized choice.
What the Molybdenum Buys
Molybdenum does one job supremely well in stainless steel: it resists pitting and crevice corrosion, the localised attack that chlorides cause. Exhaust condensate and winter road salt are both chloride sources, and they are exactly what defeats a plain stabilized ferritic over time. Grade 436 keeps the titanium stabilization that makes 439 weldable, then adds molybdenum on top so the tube resists the pitting that would otherwise perforate it from the condensate side. It is a targeted upgrade: same weldability, meaningfully better chloride resistance, for the cost of the molybdenum.
Specifications
| Grade / UNS | 436 / UNS S43600 |
| Type | Molybdenum-bearing, stabilized ferritic stainless |
| Chromium | 16.0 – 18.0% (typical) |
| Molybdenum | ~0.75 – 1.25% (the pitting-resistance addition) |
| Stabilizer | Titanium and/or niobium |
| Tube Standard | ASTM A268; confirm against order |
| Construction | ERW welded |
Applications
- Automotive Exhaust, Hot End: where temperature and chloride condensate are both present. See Automotive Steel Tubes.
- Weather-Exposed Trim: appliance and architectural trim facing outdoor chloride exposure.
- Heat Exchangers in Chloride Service: moderate chloride duty with welded construction.
- Appliance Parts Near Moisture: where plain 430 or 439 would pit.
436 Against Its Neighbours
Think of the exhaust ferritics as a ladder: 409 at the entry, 439 stabilized for welding, 436 adding molybdenum for chloride pitting, and 444 carrying still more molybdenum for the toughest condensate service. The dual-stabilized 441 sits alongside this ladder for higher-temperature exhaust duty. Pick the rung the corrosion demands and no higher. Testing follows ASTM A268 with certificates and traceability; see our Quality Policy page. Send OD, wall, and length for availability.
Related Products
- SS 439 ERW Pipes & Tubes
- Ferritic SS 444
- Ferritic SS 441
- SS 430 ERW Pipes & Tubes
- Automotive Steel Tubes
- Stainless Steel Pipes & Tubes
Frequently Asked Questions
What makes 436 better than 439 for exhaust?
Molybdenum. Both are stabilized and weldable, but 436 adds molybdenum, which resists the chloride pitting caused by exhaust condensate and road salt. Where 439 is adequate for the cooler sections, 436 suits the hot end and salt-exposed positions.
How does 436 compare with 444?
Both are molybdenum-bearing stabilized ferritics; 444 carries higher molybdenum (around 2%) for greater chloride resistance. 436 is the mid step; 444 is the step above it for the most demanding condensate service.
Is 436 weldable like 439?
Yes. It retains the titanium/niobium stabilization that keeps the weld zone corrosion-resistant, so it welds into corrosion service the same way 439 does, with the added molybdenum benefit.