A4 Stainless Steel

Stainless steel, a type of alloy, is an important part of a variety of applications. It can be used to create cookware, cutlery, major appliances, vehicles and surgical instruments.

There are many different stainless steel grades available, with each one offering unique characteristics. Some are better suited for certain environments than others.

Corrosion Resistance

A4 stainless steel is a marine grade alloy which contains a higher chrome and molybdenum content than A2. This makes it a good choice for environments where resistance to pitting corrosion in chloride environments is essential.

It is also a common choice in chemical and solvent solutions, inks, photographic chemicals and surgical implants. It can withstand exposure to sulfuric acid, bromine and iodine in water.

The chromium in the alloy creates a protective oxide layer on the surface of the material. This layer protects the metal from oxidation corrosion and prevents the formation of rust.

The number of chromium atoms per millimeter of surface area (or percentage) determines the resistance to corrosion. Typically, stainless steel alloys contain 18% chromium and either 8%, 10% or 0% nickel.


Stainless steel has a wide range of hardness levels. While some types are hard enough to be used for precision machining, others can be a little soft.

A4 is a type of stainless steel with a high amount of molybdenum and chromium. This helps it resist corrosion from a variety of different chemical processes.

Additionally, the steel has an enhanced tensile strength and fatigue resistance. This makes it an ideal material for a variety of different applications.

A4 stainless steel is often called marine grade, due to its ability to withstand harsh environments. It is also used for medical implants, surgical devices, inks, photographic chemicals, and more. This grade is similar to A2 but has slightly higher chromium and molybdenum content, resulting in enhanced corrosion resistance and greater tensile strength.


The weldability of stainless steels is generally good. However, joint surfaces and filler metal should be free from oxide, organic material, or other contamination to avoid corrosion.

A4 is a marine grade and is often referred to as 18/10 stainless or 316 (this is the chromium and nickel content- 18%Cr and 10%Ni). The addition of molybdenum in A4 makes it more resistant to pitting corrosion, which is often common with marine environments.

When welding stainless steel to carbon steel, two issues can cause problems. First, oxidation of the stainless steel alloys in GMAW can create an arc that may lose some aluminum or titanium. Second, highly restrained joints can create high stresses that could crack the weld.

Choosing the right filler metal and following proper welding procedures can help reduce these concerns. It is also important to keep the work areas separate from each other.

Tensile Strength

A4 stainless steel is a high tensile strength material that offers exceptional resistance to corrosion. Its high chromium content, along with the addition of molybdenum, gives it increased resistance in chemical and outdoor environments.

It also has superior tensile strength and high toughness, making it a preferred choice for applications that require high levels of durability. It also has good formability, weldability, and ductility, as well as excellent fatigue strength.

A4 stainless is one of the most versatile materials, and it is suitable for a wide range of uses. It has an impressive combination of properties, including excellent corrosion resistance up to 600degF, superior tensile strength up to 800 MPa, high malleability up to 650degF, and excellent formability up to 250degF. It also has good weldability & ductility, and low thermal expansion coefficients.

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