Galvanized Steel vs Stainless Steel

Galvanized steel vs stainless steel

Galvanized and Stainless Steel both are used to prevent corrosion in various industries and applications. When comparing Galvanized Steel vs Stainless Steel, both solutions resist corrosion and rusting. Find a few useful topics to understand the difference between Stainless Steel and Galvanized.

Table of contents

Corrosion Resistance Comparison Between Stainless Steel and Galvanized Steel

Corrosion Resistance Comparison Between Stainless Steel and Galvanized Steel

Galvanized Steel vs Stainless Steel

Stainless Steel A corrosian resistant alloy, comes in various grades including 200, 300, 400 series
Galvanized Steel This is zinc layer or coating which help to prevent the base steel from rust

Features of Galvanized Steel Vs Stainless Steel

Galvanized Steel Stainless Steel
Galvanized Steel Stainless Steel
Galvanizing is an Easy Coating process Corrosion and heat resistant
Prevent from rust Good machineability
Tough coating via various methods such as Hot-Dip Galvanized and continuous galvanizing Versatile and engineering steel
Pure zinc coating 4 Categories includes Austenitic, Ferritic, Martensitic and Duplex steels
Used for Bridges, transmission towers, fasteners, structures, agricultural and transportation Suitable for Marine, Shipbuilding, Aerospace, Food Industry, Railway and Automotive

Galvanizing Steel Coating Thickness Designation and Specification

Steel Type Specification
Galvanized Steel – ASTM A653
– ASTM A123
– G90
– Coating thickness of 0.9 oz/ft2
– Coating mass in grams per square meter (g/m²)
– Coating thickness in micrometers (µm)

Check the Difference Between Zinc Galvanizing Process and Electro Galvanizing

Electro Galvanized Steel Galvanized Steel
  • Can create various finishes
  • Thinner and more decorative
  • Coating Thickness: 5 to 12 microns
  • Precise process, no dramatic changes
  • Long-term protection against rust and corrosion
  • Thicker and more durable
  • More affordable for large-scale projects
  • Ideal for Industrial applications
Applications of Galvanized Steel Vs Stainless Steel

Applications of Galvanized Steel Vs Stainless Steel

Galvanized Steel Stainless Steel
  • Automotive body panels
  • Structural applications
  • Bridges and construction
  • Transportation
  • HVAC duct
  • Roofing
  • Automotive
  • Food and Dairy Industry
  • Shipbuilding & Offshore
  • Aerospace
  • Railway
  • Pharmaceutical
Protection types of Galvanized Steel and Stainless Steel
  • Galvanized Steel: A Protection layer of zinc
  • Stainless Steel: A Protection layer of oxide, which is more durable compared to Galvanized

Appearance Differences between Stainless Steel and Galvanized Steel

  • Stainless Steel finish types: Abrasive, 2B, 2D, Mirror, Brushed, Bright, Electropolished
  • Galvanized Surface: Spangles, Grey

Hot-Dip Galvanizing Process

Hot-Dip Galvanizing Process

Hot Dip Galvanized Steel Steps

  • Cleaning Cycle
  • Fluxing
  • Galvanizing
  • Post Treatment

Hot Dip Galvanizing Properties

  • Ideal for Demanding Environment
  • Superior Long-Term Protection
  • Costs Less & Lasts Longer

Mechanical Strength of Stainless and Galvanized Steel

Material Tensile Strength Yield Strength
MPa PSI MPa PSI
Stainless Steel 689-1034 100000-150000 206-275 30000-40000
Galvanized Steel 262-427 38000-62000 144-213 21000-31000

What is G90 Galvanized Steel?

  • Refers to the coating type and weight of the coating layer that is applied to the steel
  • ‘G’ tells that the steel is galvanized coated (zinc coated)
  • ’90’ indicates weight of zinc applied
  • Weight is measured using unit ounces per square foot (oz/ft2)
  • G90 means that the zinc-coating on steel weighs 0.90oz/ft2

Galvanized Steel vs Stainless Steel Fire resistance

Galvanized Steel Stainless Steel
  • Galvanizing Coated Steel products loses their strength in extreme conditions or chemical plants
  • Stainless steel material are suitable to use during fires, avoid zinc coated stainless steel in extreme heat applications

Are Stainless Steel and Galvanized Steel Magnetic?

Galvanized Steel
  • Magnetic properties depends upon the Base metal
Stainless Steel
  • Martensitic stainless steel are magnetic
  • stainless steels with ferrite are magnetic
  • Most of the grades of Austenitic Stainless Steels are non-magnetic

Surface Types of Galvanized and Stainless Steel

Galvanized Steel
  • General Galvanizing: bright, matte, shiny
  • Continuous Galvanizing: spangle, no spangle, shiny or dull
Stainless Steel
  • 2B
  • Mirror
  • Brushed
  • Electropolished

Galvanized Steel vs Stainless Steel American Specification

Galvanizing Surface Standard
  • ASTM A653 (Thickness Standard)
  • Galvannealed: A60, A90, A120
  • Galvanized: G90, G185, G210, G235
American and Industry Standard of Stainless Steel Finish
  • ASTM B912 electropolishing
  • ISO 15730
  • ASME BPE Surface Finish, SF1 (PL) AND SF4 (PM)

ASTM A123 Galvanized Steel Coating Thickness Grade

Grade oz/ft2 mils g/m2 µm
100 2.3 3.9 705 100
85 2.0 3.3 600 85
80 1.9 3.1 565 80
75 1.7 3.0 530 75
65 1.5 2.6 460 65
60 1.4 2.4 425 60
55 1.3 2.2 390 55
50 1.2 2.0 355 50
45 1.0 1.8 320 45
35 .8 1.4 245 35

Forming Process of Stainless Steel and Galvanized Steel

Galvanized Steel
  • Blanking Process
  • Hot-Dip Galvanizing Process
  • Roll Forming Process
Stainless Steel
  • Hot Rolling
  • Cold Rolling
  • Annealing

ASTM A653 Galvanized Steel Thickness Tolerance

Thickness (mm) Allowable Deviation Width
Down Up ＞1000 – ≤1300 ≤1000
0.15 0.04 0.04 – –
0.25 0.05 0.05 – –
0.1 0.03 0.03 – –
0.2 0.05 0.05 – –
0.5 0.08 0.08 – –
0.4 – – 0.04 0.04
0.5 – – 0.05 0.045
0.6 – – 0.05 0.05
0.8 – – 0.05 0.05
1.2 – – 0.08 0.08
1.5 – – 0.08 0.08
2 0.18 0.18 – –
2.25 0.2 0.2 – –
2.5 0.23 0.23 – –
3 0.25 0.25 – –
3.25 0.3 0.3 – –
3.5 0.3 0.3 – –
4 – – 0.17 0.17
5 – – 0.17 0.17
1 – – 0.06 0.055
8 – – 0.22 0.17
6 – – 0.2 0.17

Thickness Range of ASTM A123 Galvanized Steel

Steel Thickness Range in. [mm]
Material ≥5/8 [≥16.0] ≥1/4 – < 5/8 [≥6.4 – < 16.0] ≥3/16 – < 1/4 [≥4.8 – < 6.4] ≥1/8 – 3/16 [≥3.2 – < 4.8] ≥1/16 – < 1/8 [≥1.6 – < 3.2] < 1/16 [< 1.6]
Strip and Bar 100 75 75 75 65 45
Pipe & Tubing 75 75 75 75 45 45
Plate 100 75 75 75 65 45
Forgings and Castings 100 100 100 – – –
Wire 80 80 65 60 50 35
Reinforcing Bar 100 100 – – – –
Structural Shapes 100 100 75 75 65 45

Galvanizing Steel Process

Galvanizing Steel Process

Chemical Composition of Galvanized Steel vs Stainless Steel

ASTM A653 Galvanized Steel Chemical Composition

ASTM A653 Type C P Mn S Cu Al Ni Mo Cr V Ti Cb
SS Gr 550/Gr E/ Gr 80 0.20 0.04 – 0.04 0.20 – 0.20 0.06 0.15 0.008 0.025 0.015
SS Gr 340 C3/Gr F/ Gr-50 0.25   – – 0.008
SS Gr 340 C2/Gr E/ Gr-50 0.20 – –
SS Gr 340 C1/Gr D/ Gr-50 – –
SS Gr 275/Gr C/ Gr 40 0.10 – –
SS Gr 255/Gr B/ Gr 37 0.20 – –
SS Gr 230/Gr A/ Gr 33 0.04 – –
EDDS 0.02 0.020 0.40 0.020 0.01 0.10 0.15 0.10
DDS 0.06 0.50 0.025 0.008 0.025 0.008
FS type B 0.02-0.10 0.030 –
FS type A 0.10 0.035 –
CS type C 0.08 0.100 0.60 –
CS type B 0.02 -0.15 0.030 –
CS type A 0.10 –

Composition of Stainless Steel

Grades 18-8 Stainless Steel 305 Stainless Steel 316 Stainless Steel 410 Stainless Steel
Content by weight Chrome 18% 17%-19% 16%-18% 11.5%-13.5%
Nickel 8% 8%-10% 10%-14% 0%
Carbon (max) 0.08% 0.12% 0.08% 0.15%
Molybdenum (max) 0% 0% 2% 0%

Hot Dip Galvanized Standards

  • ASTM Standards
    1. A153/A153M
    2. A123/A123M
    3. A767/A767M
  • Other Galvanizing
    1. CSA G164
    2. ISO 1461
    3. AASHTO M111
    4. AASHTO M232
  • Pre-Galvanizing
    1. ASTM A143/A143M
    2. ASTM A384/A384M
    3. ASTM A385/A385M
    4. ASTM B6
  • Post-Galvanizing
    1. ASTM A780
    2. ASTM D6386
    3. ASTM D7803
    4. ASTM E376

Mechanical Properties of ASTM A653 Galvanized Steel

ASTM A653 Type Tensile Strength (Mpa) min. Yield Strength (Mpa) min. Elongation in 50mm min.(%)
SS Gr 550/Gr E/ Gr 80 570 550 –
SS Gr 340 C3/Gr F/ Gr-50 480 340 12
SS Gr 340 C2/Gr E/ Gr-50 – 340 12
SS Gr 340 C1/Gr D/ Gr-50 450 340 12
SS Gr 275/Gr C/ Gr 40 380 275 16
SS Gr 255/Gr B/ Gr 37 360 255 18
SS Gr 230/Gr A/ Gr 33 310 230 20
EDDS – 105/170 ≥ 40
DDS – 140/240 ≥ 32
FS type B – 170/310 ≥ 26
FS type A – 170/310 ≥ 26
CS type C – 170/410 ≥ 15
CS type B – 205/380 ≥ 20
CS type A – 170/380 ≥ 20

Different Methods of Galvanizing

  • Hot-Dip Galvanizing
  • Galvannealing
  • Pre-galvanizing
  • Electrogalvanizing