Three facts that decide this page
- Cold reduced close annealed sheet behaves consistently in the press because thickness and yield are tightly controlled, which is why IS 513 and EN 10130 grades are the default for repeat stamping.
- Seven-tank pretreatment, a 16 ft × 16 ft shot blast chamber, an 18 ft × 14 ft powder booth and a curing oven sit in the same plants as fabrication, so a part is not shipped out and back for coating.
- The substrate is porous and reactive, so the derust and phosphating stages matter. Parts with lapped or hemmed joints trap pretreatment chemicals and blow out during curing, which shows as blistering along the seam. Weld spatter and heavy oxide need blasting before the tanks, not more time in them.
What changes when you powder coat CRCA
The substrate is porous and reactive, so the derust and phosphating stages matter. Parts with lapped or hemmed joints trap pretreatment chemicals and blow out during curing, which shows as blistering along the seam. Weld spatter and heavy oxide need blasting before the tanks, not more time in them.
The commercial consequence is that CRCA is priced on its own material line, not blended into a steel rate. Material grade, thickness, tolerance and finish are quoted separately from conversion, so a change of specification is visible in the price.
Tolerance, edge and finish
Ganesh quotes to the drawing first and to ISO 2768 general tolerances where the drawing is silent. For CRCA powder coating, the practical starting points are in the table below. They are starting points, not a guarantee: the part geometry, thickness and fixturing decide what can actually be held, and the quotation states the tolerance offered.
How Ganesh runs this route
Film thickness is specified and measured, not guessed: 60–80 µm is the usual architectural range and 80–120 µm is used where impact or corrosion exposure is higher. Hot-rolled IS 2062 E250 plate above 6 mm is cut and formed, not pressed, on Ganesh's route: the 12 kW fibre laser cuts to 20 mm and the 200 T brake forms to 10 mm. The route is quoted as one sequence so the customer does not have to coordinate a cutter, a former, a welder and a coater.
When powder coating is the wrong route for CRCA
Powder coating is a poor fit for parts that will be repeatedly flexed or impacted in service, and for assemblies containing heat-sensitive components. Wet paint or a zinc-rich primer is often the better specification at high build on complex geometry.
A manufacturability review before quotation is the cheapest place to find this out. Send the drawing, material, finish and annual quantity and the review comes back in writing.
Typical parts
- Enclosures and cabinets
- Rack frames and panels
- Canopy assemblies
- Shelving and furniture frames
Decision rule: when to choose powder coating
Specify powder where you need a durable, single-coat finish with good impact resistance and a wide colour range. Specify wet paint where the part needs a very thin film, a metallic or special-effect finish, or a touch-up-friendly surface. Specify blasting plus a zinc-rich primer plus a topcoat where the service environment is C4 or C5 under ISO 12944 and the part cannot be re-coated in service. For CRCA the practical constraint is rust: cut, formed and coated parts should not sit unprotected in a humid shop, and the route is sequenced so pretreatment follows fabrication within the same production window. CRCA is also the easiest material to change late: a grade swap from CR1 to CR4, or a 0.2 mm thickness change, can be made without retooling in many cases, which keeps the decision reversible while volumes are still uncertain.
What to put on the drawing
State the powder type, the RAL or approved sample, the gloss level, the film thickness range, the masking requirement and the tests expected: adhesion to ISO 2409 or ISO 4624, and salt spray to ISO 9227 with the hours stated. Say what must remain conductive. A coating specification without masking and DFT is a colour request, not a specification.
Quality evidence and inspection
DFT is measured on the production part, adhesion is checked on a sample, and colour is compared against the approved standard under a defined light source. Cure is verified against the powder supplier's window. Coating records sit with the batch, and the pretreatment chemistry is monitored per shift.
What drives the cost
Cost splits into pretreatment, powder, masking, rack loading, cure and inspection. Pretreatment is priced by area and batch; powder by area and film thickness; masking by feature count. A heavy assembly can cost more to cure than a larger, thinner panel of the same area, because oven time follows mass. On CRCA / mild steel, material is quoted as its own line at the prevailing rate for the grade and thickness, so a change of specification is visible rather than hidden in a blended rate.
| Specification | CRCA / mild steel powder coating | Ganesh limit or note |
|---|---|---|
| Grades | IS 513 CR1–CR4 (D, DD, EDD), IS 2062 E250 for hot-rolled plate | Mill certificate on request |
| Thickness | 0.5–6 mm sheet; up to 20 mm plate | Seven tank: degrease, rinse, derust, phosphate, rinse, passivate, dry |
| Tensile / property | 270–410 MPa | 7.85 g/cm³ density |
| Delivery condition | Skin-passed, oiled coil or cut sheet | Check mill certificate for grade and oiling |
| Typical yield strength | 210–350 MPa depending on grade | Higher yield needs more tonnage and more overbend |
| Springback | Low to moderate | Press brake and die both compensate |
| Powder coating | Seven tank: degrease, rinse, derust, phosphate, rinse, passivate, dry | Chemistry monitored per shift |
| Tolerance basis | ISO 2768-m unless drawing states otherwise | Critical features inspected |
| Finish | Seven-tank pretreatment then powder coat or wet paint | Specified per part |
Sources and review
- IS 513 — Cold reduced carbon steel sheets and strips · reviewed 2026-11-03
- EN 10130 — Cold rolled low carbon steel flat products · reviewed 2026-11-03
- IS 2062 — Hot rolled medium and high tensile structural steel · reviewed 2026-11-03
- ISO 12944 protective paint systems and ISO 8501-1 preparation · reviewed 2026-11-03
Combines Ganesh machine limits (Seven tank: degrease, rinse, derust, phosphate, rinse, passivate, dry) with CRCA / mild steel grade and property data. The "what changes" section is written for this material–process pair and is not reused on another page.
Send the drawing and we will check the route
Material, thickness, tolerance, finish and annual quantity are enough for a manufacturability review. Tooling is quoted separately from the piece price.
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