Stainless Steel
Stainless steel contains at least 10.5% chromium, forming a self-healing oxide film that resists rust. We supply and machine the main families: austenitic (304, 316), martensitic (410, 420, 431), ferritic (430), precipitation-hardening (17-4 PH) and duplex grades.
What it is
Austenitic grades (304, 316) are non-magnetic, very corrosion resistant and weldable, but cannot be hardened by heat treatment. Martensitic grades (410, 420, 431) can be hardened for wear and strength. 303 is a free-machining grade for high-volume turned parts, while 316 adds molybdenum for chloride resistance.
Grade choice balances corrosion resistance, strength, machinability, weldability and cost.
Typical applications
- Food, dairy and pharma equipment
- Pump shafts, valves and fittings
- Marine and chemical hardware
- Fasteners and springs
- Medical and laboratory components
Materials & grades
- 304 / 304L
- 316 / 316L
- 303 (free machining)
- 410, 420, 431 (hardenable)
- 17-4 PH, 321, 310
Points to consider
- Use 316 for chlorides and marine exposure; 304 for general use.
- Low-carbon L grades avoid sensitisation after welding.
- 303 machines best but has lower corrosion resistance and poor weldability.
- Passivate after machining to restore corrosion resistance.
Frequently asked questions
What is the difference between SS 304 and SS 316?
316 contains molybdenum, giving better resistance to chlorides, seawater and many chemicals; 304 is cheaper and fine for general use.
Is stainless steel magnetic?
Austenitic grades like 304 and 316 are essentially non-magnetic when annealed; martensitic and ferritic grades like 410 and 430 are magnetic.
Can stainless steel be hardened?
Martensitic grades (410, 420, 431) and PH grades (17-4 PH) can; austenitic grades cannot be hardened by heat treatment.