Tin Free Steel (Hi-Top)

Toyo Kohan provides a wide range of specifications and high quality tin free steel (Hi-Top) to meet the needs of our customers.
Since our founding in 1934 we have grown together with our customers through the manufacture of tin plate and tin free steel. The technology that we developed with our customers continues to evolve, and we are now focusing on new uses that can contribute to the solving of environmental problems.

Toyo Kohan in Your Everyday Life
Crown Caps

Feature

Features 1 Secure processability

  • Very strong paint adhesion that makes processing easier.

Features 2 High heat resistance

  • Has high heat resistance, so that it can withstand high temperature baking finishes (up to about 400 ℃).

Features 3 Excellent corrosion resistance

  • Although the coating is very thin, it has excellent corrosion resistance.
  • Good reaction with paints, so that the surface is beautiful after painting.
  • Resistant to alkalines and neutral pH, so that it can be used without painting in certain situations.
  • Complies with the Food Sanitation Act.
Product name Basic composition Features
Hi-Top (HT) The electrolytic chromate process is applied to cold rolled steel sheet. This product (Hi-Top) was introduced by Toyo Kohan in 1961 as an alternative to expensive tin plating.
WHT2 A very thin tin plate is applied to the surface of steel sheet, so that there is no need to grind the plating surface before welding. This prevents the production equipment from being polluted by the grinding residue.
This material has better lubricating properties with tools compared with Hi-Top, so that machining lubricant is not necessary.
Uses

From standard industry products to leading-edge products, this product is used in the lives of people around the world.

  • Food cans
  • Beverage cans and metal caps
  • 18-liter cans
  • Candy cans
  • Spray cans
  • External parts for home appliances
  • Electrical and electronic parts
Production Process

In order to assure the properties suitable for various uses, tin plate used as material for cans and other purposes is made under strict quality control.

Manufacturing Process

Five-stand tandem cold rolling mill

Five-stand tandem cold rolling mill

Continuous annealing line

Continuous annealing line

Hi-Top Line

Hi-Top Line

Properties
Product Tin Hi-Top
Tin (Sn=2.8 g/m²) LTS Hi-Top(TFS) WHT-2
Weldability RC value (mΩ) *1 0.1 to 0.3 0.1 to 0.3 100 to 200 0.1 to 0.3
Assessment Good Good Bad Good
Rust proofing Salt spray test *2 Excellent Good Poor Poor
Coating materials Cup process adhesion test *3 Poor Good Excellent Excellent
Adhesion T peel test *4 Poor Good Excellent Excellent
(Remarks)
  1. RC value: Test materials heat processed for 20 minutes at 205 degree centigrade then contact electrical resistance is measured using our company's RC measuring instruments (RC value: Small → Weldability: Good)
  2. Salt spray test: 35 degree centigrade, 5% salt solution sprayed for 2 hours → visual inspection
  3. Cup process adhesion test: Lacquer coating → cup process→ cup wall surface coated film strength peeled with tape → visual inspection
  4. T peel test: Lacquer coating → Cut to 5 mm width → 2 test material sheets thermally compressed via nylon film → Measure peeling stress

Weldability

The following diagram shows an example of the weldable current range using manufactured can seam welder. Good welding materials possess a wide weldable current range.

Weldability
Available Sizes

The manufacturable range depends on the combination of each specification (thickness, width, temper etc.).
Ask us especially about combination specifications with sheet thickness upper and lower limits and sheet width upper limits.
Also ask us about specifications as needed.

Sheet

  Normal manufacturing range Manufacturable range
Sheet Thickness (mm) 0.15 to 0.50 0.13 to 0.60
Sheet Width (mm) - 670 to 1,060
Length (mm) 510 to 1,070 460 to 1,110

Coil

  Normal manufacturing range Manufacturable range
Sheet Thickness
(mm)		 0.15 to 0.60 0.07 to 0.80
Sheet Width
(mm)		 - 670 to 1,060

Hoop

  Normal manufacturing range Manufacturable range
Sheet Thickness
(mm)		 0.15 to 0.50 0.13 to 0.60
Sheet Width
(mm)		 30 to 500 10 to 500

Standard Products

Tin is manufactured under strict quality controls based on standards comparable to JIS G 3315.

Tempering (Temper Grade)

  Tempering Codes Hardness (HR-30T) Features Main Uses
Single press roll T-1 49±5 Especially good flexibility Deep draw cans, caps, etc.
T-2 53±5 Medium flexibility and strength General drawn cans, caps, etc.
T-2.5 55±5 Flexibility and adequate strength General food cans, etc.
T-3 57±5 Moderate strength General food cans, etc.
T-4 61±5 Relatively high strength Bodies, tops, bottoms, and caps of general cans, etc.
T-5 65±5 Superior bend resistance Large cans, internal pressure cans, etc.
Double press roll DR-8 73±5 Superior rigidity and strength Bodies of carbonated drink and beer cans, etc.
DR-9 76±5 Superior rigidity and strength Tops of carbonated drink and beer cans, etc.
DR-9M 77±5 Superior rigidity and strength Tops of carbonated drink and beer cans, etc.
DR-10 80±5 Excellent rigidity and strength Lids of 18-liter cans, etc.

Plating amount

Units: mg/m² (single side)
Metallic chromium layer Chromium hydrated oxide layer
Minimum Max Minimum Max
50 150 5 35

Surface finish

Surface finishing name Code Surface roughness Target value
µmRa		 Features
Bright B 0.25 Gloss finish for general purposes.
Light roughness side BR 0.30 Lightly grinded finish only used for double rolled products.
Rough R1 0.40 An original whetstone-like finish on which scratches do not show up.
Matte M 1 Dull finish without any orientation.
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