Electrolytic Tinplate Coil Matched to Your Packaging Line
Choosing tinplate starts with the package you need to make. The steel must form correctly, the surface must suit your coating process, and the coil must fit your equipment. GDD Metal supplies electrolytic tinplate coil with thickness, temper, tin coating and coil dimensions specified together for can bodies, ends, closures and decorative packaging.
Electrolytic tinplate, often called ETP, consists of thin cold-rolled steel with an electrodeposited tin coating. The steel provides structural strength, while the tin-coated surface supports packaging operations such as lacquering, printing and resistance welding. Coil supply allows processors to select their own slit widths and blank layouts.
Product Specifications
| Parameter | Specification |
|---|---|
| Material | Electrolytically tin-coated low-carbon steel; ETP / SPTE |
| Thickness | 0.13–0.50 mm, subject to grade and production route |
| Width | 600–1250 mm; slit widths by agreement |
| Temper options | SR: T1–T5; selected DR grades including DR8 and DR9, subject to the agreed standard |
| Equal tin coating | 2.8/2.8, 5.6/5.6, 8.4/8.4 and 11.2/11.2 g/m²; other options by inquiry |
| Differential tin coating | For example, 5.6/2.8 g/m²; specify the required coating on each face |
| Surface finish | Bright, stone, silver or matte, subject to specification |
| Annealing | Batch annealed or continuously annealed, as agreed |
| Coil inside diameter | 508 mm or 610 mm |
| Coil weight and outside diameter | Confirm against your uncoiler capacity and handling limits |
| Standard | JIS G 3303, EN 10202 or GB/T 2520, as specified in the order |
| Processing | Slitting and cut-to-length; coating and printing requirements reviewed separately |
| Documentation | MTC, Certificate of Origin, relevant food-contact test reports, export license where required, and shipping documents |
The ranges above describe supply options, not every possible combination. Confirm dimensional tolerances, coating limits, surface treatment, grade designation and inspection requirements before ordering.
Which Tin Coating Should You Choose?
2.8/2.8 g/m² means a nominal 2.8 grams of tin per square meter on each face. For one square meter of strip, the combined nominal coating mass is 5.6 grams. Coating mass describes the tin layer; it does not describe the thickness or hardness of the steel.
2.8/2.8 g/m² — Lower Tin Consumption
A candidate for packaging designs already qualified with this coating level, including suitable lacquered cans and general metal packaging. Compared with heavier coatings, it uses less tin. Confirm compatibility with the actual contents and protective coating before choosing it for cost reasons.
5.6/5.6 g/m² — More Tin on Both Faces
This specification provides twice the nominal tin mass of 2.8/2.8 on each face. It can be evaluated when the packaging specification calls for a heavier coating. It does not automatically double corrosion resistance or shelf life.
8.4/8.4 and 11.2/11.2 g/m² — Heavier Coating Options
These options increase nominal tin mass further. Select them when supported by the packaging design, filling trials or customer specification. A heavier coating adds material cost and does not remove the need to assess internal lacquer, processing conditions and storage.
5.6/2.8 g/m² — Different Coatings for Different Faces
Differential coating places more tin on one face. Compared with 5.6/5.6, this example reduces total nominal tin mass from 11.2 to 8.4 g/m², a 25% reduction in coating mass, not in the total coil price. Specify face identification and winding orientation so the correct side reaches the intended surface of the finished package.
Selection tip: Send the filling product, internal coating specification, heat-treatment conditions and intended storage period with your inquiry. These details are more useful than selecting tin coating by price alone.
Match Temper, Finish and Coil Format
Temper: SR and DR material behave differently during forming. A harder or thinner grade should be validated against your drawing, flanging or end-forming operations before substitution. Share the current material specification and component drawing when requesting an alternative.
Surface: Agree the finish together with the printing or lacquer process. A visually bright sample alone does not confirm coating adhesion or suitability for the finished package.
Coil format: Confirm maximum coil weight, outside diameter, inside diameter, slit-width tolerance and allowable edge burr. For sheet-fed printing equipment, our tinplate sheets may be a more direct purchasing option.
Applications and Practical Selection Examples
ETP is used for three-piece can bodies, selected drawn cans, conventional and easy-open ends, twist-off closures, paint containers and printed gift tins. The following examples illustrate procurement decisions; they are not customer testimonials or verified project results.
Example 1 — A Tomato Paste Can Body
A can maker needs material for a welded body that will be internally lacquered and thermally processed after filling. The inquiry should include can diameter and height, blank dimensions, weld-margin requirements, food composition and the approved lacquer system. Candidate material should be assessed through welding, flanging, seaming and filled-pack trials before a production change is approved.
Example 2 — Pet Food Easy-Open Ends
An end producer needs a grade compatible with its shell press, score tooling and tab design. The useful inputs are end diameter, existing gauge and temper, opening-force limits and processing conditions. Trial ends should be checked for score consistency, opening performance, pressure resistance and coating integrity. Buyers seeking finished components can explore our tinplate lids and easy-open ends.
Example 3 — Printed Tea or Gift Tins
A metal printer needs flat blanks with a consistent appearance and dimensions suited to its press. Start with the artwork layout, sheet size, finish and forming depth. Compare coil conversion with purchasing cut sheets, then check a printed and formed sample for registration, surface appearance and coating damage at bends.
Inspection, Food-Contact Reports and Export Support
GDD Metal can provide an MTC and supporting inspection documentation according to the order. Agree the required checks in advance, including dimensions, mechanical properties, tin coating on each face, surface condition and coil identification. This helps connect the delivered material with its inspection records.
Relevant food-contact test reports can be provided for products within the report scope. The tested material, any organic coating, test conditions and intended use must match the supply requirement. An MTC records material information; it does not replace food-contact testing or finished-package validation.
We support export shipments with a Certificate of Origin, MTC, applicable food-contact test reports, export license where required, commercial invoice, packing list, bill of lading and customs documentation. Tell us the destination and document requirements before order confirmation so the shipment paperwork can be coordinated.
Export packing can include moisture-resistant wrapping, protective covers, edge protection, strapping and suitable supports. Specify unloading arrangements and handling limits when ordering. Store coils indoors in dry conditions and protect them from condensation and surface damage.
Frequently Asked Questions
Are ETP and SPTE the same thing?
ETP describes electrolytic tinplate; SPTE is a designation used for electrolytic tinplate in JIS specifications. Neither term alone defines the complete order. Include the standard, thickness, temper, coating and finish.
Will a heavier tin coating always solve corrosion problems?
No. First review the contents, lacquer system, coating damage, seams and storage conditions. Compare candidate materials through relevant package testing rather than assuming that more tin will correct every failure.
Can I replace SR tinplate with DR at the same thickness?
Only after technical evaluation. The change affects forming behavior and may require tooling or process adjustments. Use a trial run to check the actual component before approving the substitution.
Is tinplate coil supplied ready for direct food contact?
That depends on the agreed material and packaging system. Specify whether you need metallic tinplate for further processing or a product with an approved organic coating. Confirm the applicable test report and intended conditions of use.
Can you supply slit coils or material for printing?
Slitting and cut-to-length requirements can be reviewed with your inquiry. For printing, provide the sheet layout and coating requirements so the supplied format matches the process.
What are the MOQ and delivery time?
Both depend on the selected specification, available material, processing and order quantity. Include your required tonnage and delivery date so we can confirm them with the quotation.
Request a Specification-Based Quotation
Send your thickness, width, temper, tin coating on each face, quantity and application. Add coil ID, maximum coil weight, surface finish, destination port and required reports when available.
If you are changing suppliers, share the current specification or an MTC with confidential details removed. GDD Metal can review the requested supply options and identify details that need confirmation.
Email: ethan@gddmetal.com
