Does Stainless Steel Rust Or Tarnish, And Why?

Sat, 09 Sep 2023 23:37:05 +0800

Does Stainless Steel Rust?

In general, stainless steel does not rust, but if it is used or maintained improperly, or in a harsh environment, it will rust or tarnish, for example, the photo above shows a stainless steel shackle on a cruise ship corrodes due to long-term exposure to the marine environment, the surface appears brown rust and spots.

The reason why stainless steel does not rust is because it contains chromium (Cr) and nickel (Ni). These two metal elements will form a dense oxide film with oxygen, this layer of oxide is also called a passivation film, which enhances the corrosion resistance. When the surface of stainless steel is scratched, it will instantly form a new oxide film, thus preventing it from further rusting and corrosion.

Why Does Stainless Steel Rust or Tarnish?

Stainless steel rust because the oxide film on its surface is continuously destroyed, therefore loses its rust proof effect, resulting in the continuous oxidation of iron.

What Causes Stainless Steel to Rust?

Halides are one of the most serious factors that cause stainless steel to rust, they can destroy the passivation film. Halides include chloride, fluoride, bromide, iodide and some inter-halogen compounds. Among them, chloride is the most common in nature and daily life. For example, chlorine ions (Cl-) are widely present in salt, sauce, physiological saline, bleach, disinfectant, salt water lake, and sea water, etc. If stainless steel is polluted by these factors for a long time and is not cleaned in time, it will rust or tarnish.

Other factors that can cause stainless steel to rust include: long-term exposure to inorganic acids such as nitric acid, sulfuric acid, hydrochloric acid, hydrofluoric acid, etc. Organic acids such as acetic acid, formic acid, etc. Alkaline such as sodium hydroxide (NaOH), etc.

Different Grades of Stainless Steel Have Different Corrosion Resistance

Different grades of stainless steel have different rust resistance due to different Cr-Ni content. Other chemical elements that affect corrosion resistance are: contents of carbon (C), phosphorus (P), sulfur (S), molybdenum (Mo), titanium (Ti), copper (Cu), niobium (Nb), etc.

According to the organization methods, they can be divided into 4 classifications:

Austenite: 200 (essentially Cr-Mn alloys) and 300 series (essentially Cr-Ni alloys), for example, 201, 302, 304 (18/8 stainless steel), 310, 316, 317, 321, etc.

Ferrite: essentially Fe-Cr alloys, 400 series, such as 430

Martensite: essentially Fe-Cr-C alloys, 400 series, such as 410, 420, 440, etc.

Duplex stainless steel: including 2204, 2205, 2507, etc.

In terms of chloride corrosion resistance, the rust resistance ranking of common stainless steel grades is as follows:
904L > 2205 > 316L > 316 > 304L > 304 > 302 > 201 > 430 > 440.

Flag Size (Avoid overloading any flagpole)

Mon, 08 Nov 2021 18:54:38 +0800

According to popular usage, the length of the flag should be between one-quarter and one-third the height of the flagpole.

Avoid overloading any flagpole!

Two big factors are the material of the flag being used and the amount of wind your flag is exposed to.

Lightweight polyester flags will fly in the lightest breeze, but are not nearly as durable as nylon or industrial polyester.

If your property is surrounded by trees, tall buildings, or any other obstructions; then your flag probably won't get as much of a breeze as a flagpole sitting out in the open.

If in doubt, go with the smaller size flag. A flag which is too large will only droop on the pole, which is probably not the reason you have a flagpole in the first place!

Height of Pole	1/4	1/3	Flag Size
20'	5'	6.67'	3x5' or 4x6'
25'	6.25'	8.33'	4x6' or 5x8'
30'	7.5'	10'	5x8' to 6x10'
35'	8.75'	11.67'	5x8' to 8x12'
40'	10'	13.33'	6x10' or 8x12'
50'	12.5'	16.67'	8x12' to 10x15'
60'	15'	20'	10x15' to 12x18'
70'	17.5'	23.33'	12x18' or 15x25'
80'	20'	26.67'	12x18' to 20x30'
90'	22.5'	30'	15x25' or 20x30'
100'	25'	33.33'	15x25' to 20x38'

Golden Color Ball Top Round Finial For Stainless Steel Flagpole

Mon, 08 Nov 2021 12:50:04 +0800

Our factory manufacture and supply Golden Color Ball Top Round Finial For Stainless Steel Flagpole. We specialize in Custom Made that you design.

Technical Details

Material: SUS304 Grade, SUS316 Grade

Shape: Round

Finish: Polished

Technics: Welded

Diameter: 180mm, 200mm, 220mm, 250mm, 300mm

Stainless Steel Base Cover Custom Made For Flagpoles

Mon, 08 Nov 2021 00:17:44 +0800

Our factory manufacture and supply Stainless Steel Base Cover Custom Made For Flagpoles. We specialize in Custom Made that you design.

Technical Details

Material: SUS304 Grade, SUS316 Grade

Shape: Round

Finish: Satin or Mirror Polished

Diameter: 380mm, 400mm, 500mm, 600mm, 800mm

Original Silver Color Ball Top Round Finial For Stainless Steel Flagpole

Sun, 07 Nov 2021 23:55:01 +0800

Our factory manufacture and supply Original Silver Color Ball Top Round Finial For Stainless Steel Flagpole. We specialize in Custom Made that you design.

Technical Details

Material: SUS304 Grade, SUS316 Grade

Shape: Round

Finish: Polished

Technics: Welded

Diameter: 180mm, 200mm, 220mm, 250mm, 300mm

Flag Stick For Stainless Steel Flagpole

Sun, 07 Nov 2021 23:39:00 +0800

Our factory manufacture and supply Flag Stick For Stainless Steel Flagpole. We specialize in Custom Made that you design.

Specification

Material: SUS304, SUS316
Finish: Satin or Mirror

Small Counterweight Weight Bead For Stainless Steel Flagpole

Sun, 07 Nov 2021 23:13:21 +0800

Our factory manufacture and supply Small Counterweight Weight Bead For Stainless Steel Flagpole. We specialize in Custom Made that you design.

Big Manual Winch For Stainless Steel Flagpoles Custom Made

Sun, 07 Nov 2021 22:58:18 +0800

Our factory manufacture and supply Big Manual Winch For Stainless Steel Flagpoles Custom Made. We specialize in Custom Made that you design.

Applications

These manual winches are for use on flagpoles 20m to 30m height. The winch is provided inside the flagpole to raise and lower the flag by use of a removable hand crank.

Features

These gearless winches utilize cast bronze internal brakes, the center axis will rotates when a winch handle is inserted and rotational pressure is applied. The flagpole winch will lock in any position by removing the handle which engages the brake system. The flagpole winch contains an automatic brake system to permit locking of the flag in any position.

Steel Halyard

Recommended diameter of stainless steel cable is 2.0mm, 3.0mm or 4.0mm.

Rasing Flag Manual Winch For Stainless Steel Flagpoles

Sun, 07 Nov 2021 22:40:27 +0800

Our factory manufacture and supply Rasing Flag Manual Winch For Stainless Steel Flagpoles. We specialize in Custom Made that you design.

Applications

These manual winches are for use on flagpoles with bottom diameters of 140mm or larger. The winch is provided inside the flagpole to raise and lower the flag by use of a removable hand crank.

Features

Steel Halyard

Recommended diameter of stainless steel cable is 1.5mm or 2.0mm.

Stainless Steel Perforated Panel Single Side Satin Finish Laser Cut

Sun, 31 Oct 2021 22:28:03 +0800

Our factory manufacture and supply Stainless Steel Perforated Panel Single Side Satin Finish Laser Cut. We specialize in Custom Made that you design.

Technical Details

Material: SUS201, SUS304, SUS316/SUS316L

Thickness: 2.0mm

Size: 1.20mx2.40m or other size

Finish: Single Side Satin Finish after Laser Cut, Brush Line direction follow as length direction.