Material selection decision
Stainless steel covers multiple alloy families, conditions and product forms whose corrosion, strength, machining, forming and welding behavior differ. Selecting 304, 316 or another grade requires the actual environment and finished component, not the word stainless alone. MakeNexa reviews supplier-network routes while exact grade, process, testing, price and timing remain RFQ-specific.
Selection criteria
List the media, concentration, temperature, cleaning, moisture, chlorides, crevices, galvanic contacts and time that shape corrosion risk. Add mechanical load, magnetic response, appearance, welding and heat requirements. Stainless Steel 304 and 316 are common decision points, but family-level familiarity does not prove performance in a particular assembly. Precipitation-hardening, ferritic, martensitic or other grades may create different heat-treatment, machining and evidence needs.
Submit exact grade and condition where frozen, or provide the properties and restrictions that a proposed material must satisfy. Identify bar, plate, sheet, casting or other form, because availability and properties may vary with form and condition. Define welding, heat tint, cleaning, passivation, electropolishing or other final processing plus the material and inspection records required. MakeNexa does not infer corrosion resistance, regulated suitability or compliance from the family name.
Where the material fits
The right family depends on environment, manufacturing history and final surface together.
Describe chemicals, chlorides, temperature, wet-dry cycling, cleaning, deposits, crevices and dissimilar metals. Use application-specific engineering data and testing where risk requires it rather than relying on a broad corrosion-resistant label.
Grade, condition, stock, work hardening, tool access, thin walls and heat influence the machining route. Mark critical surface, burr and distortion requirements, especially where later treatment changes the accepted state.
Thickness, bend, grain, springback, joint, filler, heat input and distortion matter for fabricated stainless. Define weld appearance, heat-tint removal, leak or structural inspection and final dimensions.
Cleaning, oxide removal, passivation and protected handling address different conditions. Cite the governing requirement, starting surface, allowed method, verification and packaging rather than using passivation as a universal repair note.
Material tradeoffs
Grade, condition and processing history can change both manufacturability and service behavior.
The two common grades differ in composition and are chosen from specific environment, supply, forming, welding and evidence needs. Neither label proves performance without the real exposure and final component design.
Cold work, heat treatment and product form can affect strength, hardness, machining and magnetic behavior. State the required delivered condition and any later processing that changes it.
Weld metal, heat-affected zone, oxide, distortion and surface restoration create their own route. Define preparation, filler, acceptance, cleaning and final treatment when the joint matters.
Shared tools, racks, media, bins and packaging can transfer unwanted material. Identify cleanliness and handling needs across machining, fabrication, passivation and delivery.
Grade and route choices
Use grade pages as deeper decisions after the application has established the relevant environment and route.
Review Stainless Steel 304 for compatible general corrosion, forming, welding and machining contexts, while confirming condition, environment, finish, material records and any regulated requirements for the exact part.
Review Stainless Steel 316 where its alloy family may better fit the defined exposure. Confirm exact grade variant, product form, temperature, fabrication history, passivation and project-specific corrosion evidence.
Strength, hardness, temperature, magnetism or different corrosion needs may point to another stainless family. Return the exact grade, condition, heat treatment, supply and validation consequences before substitution.
Material comparison
Typical published values for one representative grade per family. Actual values vary with grade, condition, product form and the supplier's material certification, and the project requirement is confirmed on the reviewed quote rather than from this table.
| Family and representative grade | Typical published strength and hardness | What the family is chosen for |
|---|---|---|
| Austenitic — 304, annealed | 215 MPa / 31 ksi yield, 505 MPa / 73 ksi ultimate, about 70 HRB | The general-purpose default: formable, weldable, essentially non-magnetic, not hardenable by heat treatment |
| Austenitic — 316, annealed | 205 MPa / 30 ksi yield, 515 MPa / 75 ksi ultimate | Chloride service: 2 to 3% molybdenum lifts the pitting resistance number from about 18 to 20 up to 24 to 26 |
| Austenitic free-machining — 303 | About 240 MPa / 35 ksi yield annealed, machinability around 78% against 45% for 304 | Volume turning; sulphur additions cost corrosion resistance and weldability |
| Martensitic — 410 | 275 MPa / 40 ksi yield annealed, up to about 1000 MPa / 145 ksi and 41 HRC hardened | Hardness and wear; magnetic, and corrosion resistance well below 304 |
| Martensitic free-machining — 416 | Machinability about 85%, hardenable to roughly 39 HRC | Hard turned parts in volume, with the lowest corrosion resistance of the common grades |
| Precipitation hardening — 17-4 PH | 760 MPa / 110 ksi yield in Condition A up to about 1170 MPa / 170 ksi in H900 | High strength with low ageing distortion — machine soft, age to condition |
| Ferritic — 430 | About 205 MPa / 30 ksi yield, magnetic, no nickel | Cost-driven appearance and mild-environment sheet work |
| Stiffness across every family | 193 to 200 GPa modulus | Under 4% spread — grade choice does not change how much a part deflects |
| Density across every family | 7.75 to 8.00 g/cm³, roughly three times aluminium | Mass budget against the section the strength requires |
| Common specifications | ASTM A276 for bar, ASTM A240 for sheet and plate, ASTM A582 for free-machining bar, ASTM A564 for precipitation-hardening bar | Which specification the mill certificate must reference |
Material RFQ inputs
Provide the service environment and manufacturing history needed to evaluate grade and final condition.
Complete packages move faster: revision-matched CAD, critical dimensions, quantity and material notes are enough to open engineering review across the network.
Get a QuoteSubmit the controlled model, drawing, revision and complete service environment
State exact stainless grade, condition and product form or controlling property requirements
Describe corrosion media, temperature, cleaning, crevices and dissimilar-material interfaces
Define machining, forming, welding, filler, heat treatment, distortion and weld-appearance needs
Specify cleaning, oxide removal, passivation, finish, cleanliness and protected handling
List quantities, material records, tests, inspection, documentation and packaging requirements
Questions before routing
These answers prepare the request; the reviewed quote controls project-specific commitments.
Decide on chlorides. Mechanically the two are close — 215 MPa / 31 ksi yield for 304 against 205 MPa / 30 ksi for 316, identical 193 GPa modulus and 8.00 g/cm³ density — and 316 costs commonly 1.2 to 1.5 times as much. The difference is 2 to 3% molybdenum, which lifts the pitting resistance number from roughly 18 to 20 up to 24 to 26. Indoors and dry, 304. Coastal air, de-icing salt or saline process fluid, 316.
No, and the family name hides a wide range. 316 at a pitting resistance number of 24 to 26 handles chlorides that 304 at 18 to 20 does not, and both far outperform free-machining 303 and 416, whose sulphide inclusions are pitting initiation sites. Martensitic 410 carries the minimum chromium for stainless behaviour and nothing more. Free iron from tooling, weld scale and heat tint all reduce resistance further regardless of grade. State the environment, not the family.
The austenitic grades — 304, 316, 303 — cannot be hardened by heat treatment at all; they work-harden but that is a machining problem, not a design route. For hardness, the choices are martensitic 410 or 416 at up to roughly 41 and 39 HRC, or precipitation-hardening 17-4 PH from about 33 HRC in Condition A to 40 to 44 HRC in H900. 17-4 PH is usually the better route where distortion matters, because ageing at 480 to 620 °C moves the part far less than a quench.
It depends on the grade, and this is where the L designations matter. Standard 304 and 316 allow up to 0.08% carbon, which precipitates chromium carbides in the heat-affected zone and leaves the weld line corroding faster than the parent metal; 304L and 316L cap carbon at 0.03% to prevent that, giving up about 45 MPa of yield in exchange. Free-machining 303 and 416 are not recommended for welding at all because the sulphur promotes hot cracking.
No. Passivation to ASTM A967 dissolves free iron embedded by tooling and fixturing so the chromium oxide film can reform, but it does not remove weld scale or heat tint — those need pickling or mechanical cleaning first, and a passivation step applied over them leaves the corrosion problem in place. State the sequence: descale, clean, passivate, and how each is verified.
Next step
Send the material requirement with geometry and use context. MakeNexa routes capable suppliers from a global network covering competitor-class process categories, then returns a prepared quote or focused clarification for your revision.
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