Skip to content 
What is ASTM A623M?
ASTM A623M is Unit State American Industrial Standard to Electrolytic Tinplate Sheet and Electrolytic Chromium-Coated Steel of the technical contents. This specification covers a group of common requirements, which unless otherwise specified in the purchase order or in an individual specification, shall apply to tin mill products.
In case of any conflict in requirements, the requirements of the purchase order, the individual material specification, and this general specification shall prevail in the sequence named.
ASTM A623M Equivalent of Electrolytic Tinplate Sheet and Electrolytic Chromium-Coated Steel
Chinese standard: GBT 2520
European standard: EN 10203
Japanese Industrial Standard standard: JIS G3303
Definitions Of ASTM A623M
Black plate, light-gage, low-carbon, cold-reduced steel intended for use in the untinned state or for the production of other tin mill products. It is supplied only in a dry or oiled condition.
Box annealing, a process involving slow heating of coils to a subcritical temperature, holding, and cooling there from, to recrystallize the grain, and thus, relieve stresses
produced during cold reduction. It is accomplished in a sealed container. By introducing and maintaining an inert or slightly reducing atmosphere during the cycle, a relatively bright surface is obtained.
Continuous annealing, a process consisting of passing the cold-reduced strip continuously and in a single thickness through a series of vertical passes within a furnace consisting of heating, soaking, and cooling zones to crystallize the grain and thus relieve stresses produced during cold reduction. An inert or slightly reducing atmosphere is maintained in the furnace to obtain a relatively bright strip.
Coated Style, Electrolytic Tinplate and Chromium-Coated Steel light-gage, low-carbon, cold-reduced steel on which Tinplate, chromium and chromium oxides have been electrodeposited.
Cold Reduction, the process of reducing the thickness of the strip cold, generally accomplished by one rolling through a series of four-high mills arranged in tandem.
Double-Reduced plate, plate given a second major cold reduction following annealing. Some double-reduced products are produced to achieve a minimum level of ductility in the material.
ASTM A623M Steel Grade
| Type of steel | Remark |
| MR | It contains few residual minor constituents and has a good corrosion resistance so that it is widely used for such applications as containers. |
| L | It contains particularly few residual minor constituents such as Cu, Ni, Cr, Mo, so that it is suitable for the materials of containers required improved corrosion resistance. |
| D | It is aluminium killed steel, so that it is suitable for the applications which bear deep drawing or other working that is liable to produce Luder’s lines pattern. |
Tin coating Mass of ASTM A623M
Tin coating mass and method of expressing tin coating mass. The minimum average coating mass shall be specified for tinplates and black plates with the designation of tin coating mass of l g/M2 or more on one surface. The minimum average coating mass for electrolytic tinplate shall be based on the coating mass on one surface.
Designation of standard tin coating mass and its minimum average coating mass
| Electrolytic Tinplate Sheet | ||
| Type of coating | Equally coated | Differentially coated |
| Designation of coating weight (g/m2) | 2.8/2.8 | 5.6/2.8 |
| 5.6/5.6 | 8.4/2.8 | |
| 8.4/8.4 | 8.4/5.6 | |
| 11.2/11.2 | 11.2/2.8 | |
| 11.2/5.6 | ||
| 11.2/8.4 | ||
| Nominal coating weight (g/m2) | 2.8/2.8 | 5.6/2.8 |
| 5.6/5.6 | 8.4/2.8 | |
| 8.4/8.4 | 8.4/5.6 | |
| 11.2/11.2 | 11.2/2.8 | |
| 11.2/5.6 | ||
| 11.2/8.4 | ||
| Minimum average coating weight (g/m2) | 2.45/2.45 | 5.05/2.45 |
| 5.05/5.05 | 7.55/2.45 | |
| 7.55/7.55 | 7.55/5.05 | |
| 10.1/10.1 | 10.1/2.45 | |
| 10.1/5.05 | ||
| 10.1/7.55 | ||
Temper Grade of ASTM A623M
Temper grades for single cold-reduced tinplate and black plate shall be expressed in Rockwell superficial hardness (HR30T).
Temper Designation Of Single Cold-Reduced Product
| Temper Designation | Traget, Rockwell hardness HR30T |
| T-1 | 49+3 |
| T-2 | 53+3 |
| T-2.5 | 55+3 |
| T-3 | 57+3 |
| T-4 | 61+3 |
| T-5 | 65+3 |
| T-6 | 70+3 |
Temper grades for double cold-reduced tinplate and black plate shall be expressed in Rockwell superficial hardness (HR30T).
Temper Designation Of Double Cold-Reduced Product
| Temper Designation | Target, Rockwell Hardness | Target, proof stress (information only) parallel to rolling direction |
| HR30T | N/mm2 | |
| DR-8 | 72 | 550 |
| DR-9 | 75 | 620 |
| DR-9M | 76 | 660 |
| DR-10 | 79 | 690 |
ASTM A623M Surface Treatment
Classification of surface finishes for electrolytic tinplate
| Commodity | Letter Symbol | Classification | Specific Feature |
| Single cold-reduced products | B | Bright finish | A luster surface provided by a flow-brightened tin coating on a smoothly grindstone-finished steel base. |
| R | Stone finish | A luster surface provided by a flow-brightened tin coating on a steel base characterized by a directional grindstone-pattern. | |
| S | Silver finish | A luster surface provided by a flow-brightened tin coating on a coarse dull finished steel base. |
Surface Finish Classification Of Blackplate
| Single cold-reduced products | B | Bright finish | A smooth surface finish with a fine grindstone-pattern |
| R | Stone finish | A surface finish with a directional grindstone-pattern | |
| M | Matte finish | A dull surface finish | |
| Double cold-reduced products | R | Stone finish | A surface finish with a directional grindstone-pattern |
Dimensions Tolerances of ASTM A623M
Thickness Tolerances
Thickness tolerances for tinplate and black plate shall be + 10 % of the nominal thickness. Usually we can control the thickness tolerance according to the customer’s requirements.
Width Tolerances
Width tolerances shall be 3mm of the specified width.
Length Tolerances
Length tolerances for sheet and black plate sheet shall be 5 mm of the specified length. However, the tolerances should fall within 3 mm.
| Number of coils of one lot | Length tolerance % |
| 1 to 4 | 3.5 |
| 5 to 99 | 3 |
| 100 and over | 1 |
The above is a display of the main parameters in the ASTM A623M production standard. I hope it can help you better understand Tinplate. If you are looking for a Tinplate supplier, we hope you can contact us to give you a quote. If you need to find other suppliers, we are happy to help you.
