Aluminized Steel Type 1

 

What is aluminized?

Aluminizing can be defined as thermo-chemical diffusion process applied to carbon steel, alloy, and stainless steels; nickel-based alloys; and nickel-iron alloys to enhance oxidation and corrosion resistance.

In simple terms Aluminium or Aluminium alloy coating is applied over a Base metal (Stainless steel, Mild Steel, Nickel Alloy, Alloy Steel).This  new combination of Coating with selection of Base material options makes it a new product  in industry which can be used for better performance, longer life and cost saving.

Aluminzed products are relatively new in the industry as compared to Galvanized steel. Often there is confusion over applications and usages of Aluminized steel products. It must be noted that, Aluminzed Type 1 & Aluminized type 2 are absolutely not substitutable products.
Since Aluminized is for a niche application, it’s important to understand what exactly is the products requirement and its benefits and risk of the product used. We explain the products as under.

aluminized

The aluminum in the coating forms aluminum oxide, which is transparent and not noticed, but which protect the underlying surface from reactions with the atmospheric oxygen. Aluminizing is a modern day engineering innovation boasting of low cost high heat resistance features.

 

Aluminized Coated: Type 1.

Why did it take place (objective)?

Mild Steel as the name suggests is holds very mild strength towards atmospheric, acidic and water corrosion.  Mild Steel is highly prone to Rusting due to Oxidation that is when Oxygen in air reacts with Fe on the surfaces and forms Fe2O3 and Fe3O4. Gradually they start disintegrating from the Surface and lead to chipping off in form of Flakes, Which eventually leadings to reduction in the Section or the thickness of the Steel article. It reduced the strength and reliability of the structure of steel article.

Stainless Steel was Invented 100 years back to fight the problems of Corrosion but the cost of Stainless Steel was quite higher then Mild Steel, commercially it was not viable to substitute Mild steel with Stainless Steel.
In order to overcome this problem of Oxidation and Corrosion resistance to Steel in commercially viable manner- Coated Steel products were introduced mostly commonly Gavanized Steel was used.

But over a period of time there were various application (thermal application & Food Grade) for which Galvanized Steel coating was not suitable hence there was a need to change to coating combination from Zinc to Aluminium or aluminium Alloy coating. When comparing Aluminized steel and stainless steel, the former ones have high thermal conductivity. Unlike the aluminized steel, the stainless steel has a high thermal expansion coefficient, which means that it could change shape when exposed to overheat.  Moreover, Aluminized steel comes with electrostatic surface and it is because of it that it is mainly used in making exhaust systems and mufflers.

With Advancing Technology and complex application in industry there was a demand for  products with Higher temperature resistance and better performances then Aluminized Steel, eventually the base metal was substituted fo Stainless Steel (409/439) and a new product was introduced ie Aluminzied Stainless Steel.

enquiry-button1

 

Aluminized steel Type1

Coating Combination

Hot-dip coated with an aluminum/silicon alloy containing 5% to 11% silicon to promote better adherence. It is intended principally for heat resisting applications and also for uses where corrosion resistance and heat are involved. Possible end users are mufflers, furnaces, ovens, ranges, heaters, water heaters, fireplaces, and baking pans.

Coating Method

Hot Dipping continuous coating method is used for production of the product, in which base metal is dipped in a Pot In this case of 88 to 91 % Aluminum to 5 to 11 % Silicon. In this method both sides are coated simultaneously.

This process assures a tight metallurgical bond between the steel sheet and its aluminium coating, producing a material with a unique combination of properties possessed neither by steel nor by aluminium alone.

Coating Designation

Coating Weight Min.

Approx. Ctg. Thickness per  side (Mils)

oz./ft2

g/m2

T1 13

0.13

40

0.25

T1 25

0.25

76

0.50

T1 26

0.26

80

0.50

T1 40

0.40

122

0.80

T1 60

0.60

183

1.20

Characteristics

Product Features

Corrosion Resistance Aluminized Steel Type 1 has superior performance compared to zinc coated materials for resistance to atmospheric and salt spray corrosion. Formability Aluminized Steel Type 1 can be used to produce parts containing simple bends to parts with deep drawing requirements. Heat Reflectivity Aluminized Steel Type 1 has excellent heat reflectivity during exposures to temperatures below 800 °F (427 °C), reflecting up to 80% of the radiant heat that impinges upon it.

High Temperature Properties Aluminized Steel Type 1 is an excellent heat resistant material effective up to 1250 °F (677 °C). ALUMI-THERM® is a product designed to provide enhanced high temperature strength at temperatures approaching 1400 °F (760 °C).

Paintability

For best results, Aluminized Steel Type 1 should be cleaned with a mild alkaline cleaner to remove dirt and oil, followed by phosphate with a zinc phosphate. Chromium and aluminum oxides also give good results as a pretreatment on coil coating lines. Mild abrasion prior to pre-treating may also be used to enhance mechanical bonding of the paint.

Weldability

A variety of welding processes can be used to join Aluminized Steel Type 1, provided that welding procedures are adapted to the special properties of the material. Resistance spot and projection welding processes are especially suited for Aluminized Steel. High frequency resistance welding and various arc welding processes are also compatible with Aluminized Steel.

Heat Resistance

The heat resistance of ACMS is excellent compared to that of zinc-coated steel sheet, galvanized steel sheet, and cold-rolled steel sheet. Absolutely no changes in appearance and discoloration are observed even under extended exposure to the temperature of 450℃. At temperatures higher than 450℃ the coating material transforms to aluminium-iron alloy layer so that heat resistance and corrosion resistance are preserved even if discoloration occurs. The coating maintains its sacrificial properties up to the temperature of approximately 600℃.

 

enquiry-button1

Heat Reflectivity

Aluminized Coated Steel provided with excellent thermal reflectivity due to the fineness of its surface. The thermal reflectivity of Aluminized Coated Steel at 450℃ reaches up to approximately 80%, and this is applied to thermal reflectors for toasters, gas ranges, oil stove, and so forth.

HEAT REFLECTIVITY  in %

Aluminized coated steel

Electro-Galvanized Sheet

Gl Sheets

Spangle

Zero – Spangle

100℃ X 24hrs.

90

90

90

90

400℃ X 24hrs.

80

30

20

20

Mechanical Properties:

MATERIAL

CLASS

CODE

TENSILE TEST

HARDNESS(HrB)

YP(kgf/mm2)

TS(kgf/mm2)

E (%)

HOT-DIPPED STEEL SHEET

Commercial

SA1C

23

36

35

40

Drawing

SA1D

21

32

38

38

Deep-Drawing

SA1E

20

31

40

35

COLD-ROLLED STEEL SHEET

Commercial

SPCC

24

34

38

36

CLASS

CODE

ELONGATION (%)

Bending Test

0.4 ≤ t < 0.6

0.6≤ t <1.0

1.0≤ t

Bend Angle

Inner Spacing of Bend

Commercial Quality

SA1C

180°C

4t

Drawing Quality

SA1D

≥30

≥32

≥34

180°C

1t(*)

Deep-Drawing Quality

SA1E

≥34

≥36

≥38

180°C

1t(*)

enquiry-button1

 

ASTM Standard

Quality Designation

YS

UTS

Elongation%

“n”

“rm”

ksi

MPa

ksi

MPa

Commercial Steel

46.5

324

55.9

386

34.1

-

-

Deep Drawing Steel

32.8

228

49.1

338

41.2

0.22

1.3

Extra Deep Drawing Steel

25.1

172

45.2

310

43.1

0.23

1.7

Extra Deep Drawing Steel Plus

23.9

165

45.1

310

44.2

0.23

1.9

DIN Standard

Quality

Use

YS (MPa)

UTS

(MPa)

Elongation %

“n”

“r”

51+AS

Roll forming – Lock seaming

270 – 500

≥ 22

52+AS

Average drawing

140 – 300

270 – 420

≥ 26

53+AS

Difficult drawing

140 – 260

270 – 380

≥ 30

54+AS

Difficult drawing

120 – 220

260 – 350

≥ 34

1.4

0.18

55+AS

Very difficult drawing 600°< T < 800°C

140 – 240

270 – 370

≥ 30

56+AS

Extra- deep drawing

120 – 180

260 – 350

≥ 39

1.7

0.20

57+AS

Extra- deep drawing

120 – 170

260 – 350

≥ 41

1.9

0.21

Chemical Composition

CLASSIFICATION

Chemical Composition (%)

C

Si

Mn

P

S

Commercial Quality

0.15&Under

-

0.50&Under

0.035&Under

0.040&Under

Drawing Quality

0.10&Under

-

0.50&Under

0.025&Under

0.035&Under

Deep-Drawing Quality

0.10&Under

-

0.50&Under

0.025&Under

0.035&Under

aluminized-applicationApplications

  • Industrial Heaters & Industrial Ovens.
  • Bakery Mould Products.
  • Household Equipments
  • Charcoal Based stoves etc.
  • Ranges.