We are Riddhi Siddhi Impex, a Mumbai-based manufacturer and supplier of Stainless Steel 304 Shims, established in 2002. We slit and supply UNS S30400 stock to ASTM A240 / ASME SA-240 and ASTM A666, from 0.03 mm to 5 mm thick, in every temper from Soft to Full Hard. As an ISO 9001, 14001, and 45001-certified company with a supply capacity of 400-500 tons monthly, we provide EN 10204 Type 3.1 / 3.2 mill test certificates on request.
Stainless Steel 304 Shims are thin flat spacers slit from the 18/8 austenitic alloy, the most widely stocked stainless grade. Chromium forms a self-repairing passive film that protects the material against atmospheric corrosion, food acids, and routine washdown chemicals. The grade also work-hardens well: cold rolling lifts tensile strength from 515 MPa annealed to 1035 MPa at Half Hard, so one alloy covers soft packing and spring-tempered duty alike. For applications requiring high yield strength, our 304 hard stainless steel shims are typically used for spacing, leveling, and aligning machinery components in automotive, food, and manufacturing industries.
As a reliable Stainless Steel 304 Shim supplier, we slit every stainless steel shim in-house rather than reselling fixed widths. Any width from 3 mm to 2000 mm ships at ±0.1 mm, in five tempers, with four surface finishes and deburred or round edges for gasket faces.
Temper describes how far a shim has been cold rolled past the annealed state, and with it, how much strength the material has gained. We supply Stainless Steel 304 Shims in five conditions: Soft (Annealed), ¼ Hard, ½ Hard, ¾ Hard, and Full Hard. ASTM A666 defines tensile and yield minimums for grade 304 up to ½ Hard only; we roll ¾ Hard and Full Hard as mill tempers, to tensile ranges agreed at order stage and recorded on the EN 10204 mill test certificate. Temper choice matters twice on a shim: once for strength under load, and again for how flat the spacer sits at our ±0.1 mm slit widths.
Annealed shims hold 515 MPa (75 ksi) tensile and 205 MPa (30 ksi) yield as minimums, with hardness capped at 92 HRB. Elongation reaches 40% minimum at standard gauges, so the material folds around irregular flange joints without cracking; below 0.38 mm that figure becomes indicative rather than a certified minimum. On our slitting lines this temper takes the gentlest handling, and narrow soft coils leave us paper interleaved to keep the surface unmarked. Gasket cutters and pipe fitters choose it for flange packing, gasket faces, and spacers formed by hand to the joint profile.
Quarter hard is the temper we quote when a caller asks for something firmer than soft that still punches cleanly. ASTM A666 sets 860 MPa (125 ksi) tensile and 515 MPa (75 ksi) yield as the minimums, and the material keeps 10% elongation, enough for blanking and light forming. Hardness of 25 HRC minimum stands as an indicative figure by customer agreement, since A666 governs this temper through tensile properties rather than Rockwell numbers. Machine erectors take it for pump alignment packs and gearbox levelling, jobs that need a spacer stiff enough to slide into a tight gap without buckling.
Half hard solves the complaint we hear most often about softer spacers: stacks that compress a fraction under bolt torque and throw out a carefully set clearance. Engine builders fit it for valve clearance packs and brake calliper mounts, where preload has to survive vibration and heat cycling. A666 minimums stand at 1035 MPa (150 ksi) tensile and 760 MPa (110 ksi) yield, the hardest condition the standard defines for grade 304, with 32 HRC minimum carried as an indicative value only. Forming range narrows at this strength, so plan on flat punched or laser-cut spacers rather than folded parts.
Buyers sometimes ask us to certify three quarter hard 304 to ASTM A666, and the honest answer is that the standard stops at half hard for this grade. We roll ¾ Hard as a mill temper instead, with the tensile range fixed when the order is placed and the achieved figures recorded on the EN 10204 Type 3.1 certificate. Springback grows at this strength, a point worth allowing for if the shim needs any secondary forming. The temper suits thin packing shims and wear strips that must resist fretting at fastener faces without going all the way to full hard stiffness.
Full hard is the wrong choice when a design needs maximum strength plus a guaranteed elongation figure; grade 301, which A666 defines through to full hard, is the correct call there. Where 304 chemistry is mandatory, we supply full hard as a mill temper rolled to an agreed tensile requirement and confirmed per order, exactly as the mechanical table above states. Expect a weak magnetic pull at this condition, since heavy cold rolling forms strain-induced martensite in the austenitic structure. Stampers order it for spring-action spacers, anti-fretting packs, and thin shims that must stay flat under repeated load.
We provide ASTM A240 Type 304 shims across the complete temper ladder, custom-slit from ready stock, with the options tabulated below.
| Parameter | Details |
|---|---|
| Standard | ASTM A240 / ASME SA-240, ASTM A666 |
| Thickness | 0.03 mm to 5 mm |
| Width | 3 mm to 2000 mm |
| Width Tolerance | ±0.1 mm |
| Temper | Soft (Annealed), ¼ Hard, ½ Hard, ¾ Hard, Full Hard |
| Supply Forms | Cold rolled |
| Surface Finish | BA (Bright Annealed), 2B, Matte, Scotch-Brite |
| Edge | Slit edge, Mill edge, Deburred edge, Round edge |
Chromium does the protective work in Type 304 Stainless Steel Shims, forming the passive oxide skin, while nickel keeps the structure austenitic and ductile.
| Element | Composition (% by weight) |
|---|---|
| Carbon (C) | 0.08 max |
| Manganese (Mn) | 2.00 max |
| Phosphorus (P) | 0.045 max |
| Sulphur (S) | 0.030 max |
| Silicon (Si) | 0.75 max |
| Chromium (Cr) | 17.5 to 19.5 |
| Nickel (Ni) | 8.0 to 10.5 |
| Nitrogen (N) | 0.10 max |
| Iron (Fe) | Balance |
Work hardening defines this product. Annealed 304 stainless shims stretch 40% minimum, punch cleanly, and still hold 10% elongation at ¼ Hard. HRC values are for reference/typical properties by customer agreement only and are not an ASTM A666 standard requirement.
| Temper | Tensile Strength (min) | Yield Strength 0.2% (min) | Hardness (indicative) |
|---|---|---|---|
|
Soft (Annealed)
|
515 MPa (75 ksi) | 205 MPa (30 ksi) | 92 HRB max |
|
¼ Hard
|
860 MPa (125 ksi) | 515 MPa (75 ksi) | 25 HRC min |
|
½ Hard
|
1035 MPa (150 ksi) | 760 MPa (110 ksi) | 32 HRC min |
|
¾ Hard, Full Hard
|
To agreed requirement | To agreed requirement | Confirmed per order |
Purchase teams ordering AISI 304 shims, 1.4301 shims, or SUS304 shim stock can match every regional designation here.
| Country / Standard | Designation |
|---|---|
| USA (UNS) | S30400 |
| Europe (EN) | X5CrNi18-10 |
| Germany (W.Nr) | 1.4301 |
| Japan (JIS) | SUS304 |
| China (GB) | 06Cr19Ni10 |
| Russia (GOST) | 08Х18Н10 |
These 4 industries account for most of the UNS S30400 shims we slit, choosing the grade for corrosion resistance at a workable price and offering a wide choice of tempers.
Engine builders set valve clearances, level gearbox housings, and pack brake calliper mounts with SS 304 shims. Cold-worked tempers hold preload through vibration and heat cycling, and the alloy ignores road salt that destroys carbon steel spacers.
Dairy, brewery, and pharmaceutical fitters level mixer mounts, filler heads, and conveyor rails on 18/8 stainless steel shims. Daily caustic washdowns leave the passive layer intact, so nothing flakes into the product stream and hygiene audits pass.
Airframe and MRO shops pack seat tracks, avionics trays, and access panels with 304 SS shims. A spacer slit to ±0.1 mm drops in without trimming, and harder tempers resist fretting at fastener faces.
Gasket cutters and machine erectors keep 304 shim stock shelved for pump alignment, coupling set-up, and flange packing. Deburred edges protect mating faces, and annealed material folds around irregular joints without cracking.
Shim orders are issued from our Mumbai and Taloja warehouses within days, packed for export sea freight.
| Parameter | Details |
|---|---|
| Packaging | Wooden cases, pallet packing |
| Incoterms | FOB, CIF, CFR, EXW Mumbai |
| Dispatch Points | Mumbai and Taloja warehouses |
| Standard Lead Time | 4 to 5 days |
| Urgent Dispatch | 2 to 3 days |
| Payment Terms | Advance, credit, LC |
| Certification | EN 10204 Type 3.1 / 3.2 mill test certificates on request |
Stainless Steel 304 Shims price in India is around ₹200 to ₹350 per kg, and export buyers generally pay about $3.5 to $4.2 per kg. The band is indicative: nickel surcharges, gauge, temper, finish, and volume all shift it. Call or WhatsApp our team for a firm rate.
SS 304 shims run from 0.03 mm to 5 mm thick in our programme, slit to any width between 3 mm and 2000 mm at ±0.1 mm.
Stainless Steel 304 Shims come in Soft (Annealed), ¼ Hard, ½ Hard, ¾ Hard, Full Hard, each confirmed by tensile strength and Rockwell hardness rather than temper name alone.
Stainless Steel 304 Shims are non-magnetic in the annealed condition. Cold rolling forms strain-induced martensite, so harder tempers show a weak magnetic pull that peaks at Full Hard.
The difference between 304 and 304L shims is carbon content: 0.08% max against 0.030% max. Standard 304 carries higher strength minimums, while 304L suits welded assemblies where sensitisation is a concern.
The price of SS 304 shims per kg falls around ₹200-₹350 in India and $3.5 to $4.2 for export enquiries. Share thickness, temper, and quantity to receive a firm figure.
You can source Stainless Steel 304 Shims in India from us at Riddhi Siddhi Impex. Our Mumbai and Taloja warehouses hold ready S30400 stock, slit and dispatched within 4 to 5 days. Phone or WhatsApp us; quotes will be provided within 24 hours.
