specification for Soudronic group welder
Sheet use range:
Can-body inside diameter 45 - 330 mm
Can-body height (BBH) 50 - 540 mm
March 2021 Headpiece overlap 0.32 - 0.8 m
Recommended sheet standards:
EN 10202:2003 (European Standard)
ISO 11949:2016 (International Standard)
ASTM A624:2018 (American Standard)
ASTM A626:2016 (American Standard)
When ordering tinplate from the manufacturer, always state the intended use.
Body blank sizes and tolerances must meet Soudronic standards 0611/0612/0613 and machine specifications.
Avoid mixing sheets of different coils and/or batches, as any significant variation of thickness, temper hardness,
material age and other parameters may reduce rounding quality, weld quality and, therefore, line efficiency.
Be careful when inserting a new stack into the slitter, as mixing in the slitter collector may result.
Always check the following machine setting data when starting a new coil:
- optimal rounding
- parallel overlap
- current setting
Tinning
The material supplied by the sheet metal manufacturer must meet tinning tolerances according to EN 10202:2003.
A free tin layer > 1.4 g/m2 is recommended on each side of the sheet in the ready-to-weld state to achieve
enough welding range. Weldability tests are recommended for sheets with tin plating ≤ 1.4 g/m2, LTS and "second choice" sheets.
Note: After printing, high temperatures during the curing process cause a reduction of the free tin layer thickness
by 0.5 g/m2 at each oven passage. Therefore, a sufficiently large initial tin thickness should be ordered.
To avoid welding problems due to edge tinning, sheets must be trimmed sufficiently in the slitter according to
Soudronic slitter specifications.
Tin layer thickness variations must not exceed ±10% of the nominal value along welding edges. If a larger tin
layer tolerance occurs, increase trim values on slitter to reduce the probability of welding problems (e.g. cold
spots).
Hardness and mechanical properties
Sheet metal grades: TS / TH 230 – 550
Other grades: validation by trial
To avoid a negative impact on line efficiency and/or product quality, the following must be taken into account:
- Rolling direction is preferably circumferential (C-grain). Rolling direction along the can height (H-grain) will rather cause processing problems (e.g. flange cracks).
- Do not mix sheet grades with different annealing treatment (TS/TH) or reduction (e.g. SR/DR).
- Do not mix sheet grades with different rolling directions (C-/H-grain).
- Do not mix sheet grades with different material properties (e.g. thickness, temper, tinning, litho, etc.)
- Do not use sheet grades showing signs of internal stress (e.g. waviness).
Note: Ductility is reduced in double-reduced (DR) grades. This can adversely affect subsequent operations (e.g. flanging, necking).
Ductility depends not only on the standard tolerance (yield strength) but also on other factors not specified in the European Standard.
Therefore, special provisions (tolerance specifications) should be agreed on if high downstream processing
requirements (small can diameter, scored cans, large flange width; high welding, flanging and necking speed)
are involved.
Other factors that also have an influence on downstream processing are can diameter, flange width and
flanging. Spin flanging is recommended for DR qualities, especially at high strain rates.
Surface and welding edges
A lacquer margin > 2 mm is required at each welding edge. The maximum value is defined by the seam protection width.
To avoid processing problems (e.g. destacking or welding problems), the welding edge of the lacquered sheets must not be soiled by lacquer blobs or condensation,
and must be free of corrosion, packaging residues (e.g.wood, plastics), printing/alignment marks or any other contamination.
TFS sheets (ECCS, TCCT/ECCS-RC, and black plate) need lacquering on both sides to allow further processing. Otherwise, increased machine wear must be expected.
TFS (Tin Free Steel): ECCS, TCCT/ECCS-RC and blackplate
Weldability must be verified in advance for these sheet grades, as it depends, among other things, on the surface quality of the welding edges.