Properties of & Uses for 8620 Grade Steel

Stainless steel is commonly used for appliances, such as refridgerators.
••• Ryan McVay/Photodisc/Getty Images

The steel alloy of grade 8620 is also called nickel-chromium-molybdenum steel. It is a sturdy alloy, largely composed of carbon, with many uses in the manufacturing trades. Properly hardened and formed, it can be used to make hard-wearing machine parts.

Composition

8620 alloy steel is composed of (in descending order of percentage) iron, carbon, silicon, molybdenum, manganese, nickel, chromium, sulphur and phosphorus. These ingredient elements must be within certain weight percentages to create the 8620 alloy. It is recommended that the steel be hardened by carburization followed by an oil, as opposed to water, quench. It has a fairly average density for steel alloys at .28 lb. per square inch, although its tensile strength — the amount of weight that it can hold before breaking — is low, at 536.4 Mpa. The average tensile strength of steel alloys is 758 to 1882 Mpa. It should be forged at 2,200 degrees Fahrenheit, and melts at 2,600 degrees Fahrenheit. It is not very efficient at transmitting heat, and does not deform easily under low heat.

Uses

When the 8620 alloy is properly carburized — heated to a set temperature and then exposed to an agent containing carbon, a process which adds an extra layer of carbon to the outside of the steel, thereby making it stronger — it is used to make such machine parts as gears, crankshafts, and gear rings. Carburized 8620 alloy is strong and durable, which is why it is preferred for these parts.

Working

Steel of an 8620 alloy can be worked into shape through pounding, rolling or bending prior to carburizing, although after carburizing it is recommended only finish machining (such as polishing) be done to prevent weakening the outer layers of the steel. Extensive carving on the surface could remove the extra layers of carbon, leaving the worked part weak.

Welding

Some pieces made of the alloy are either too intricately shaped or large to be made out of one piece of steel. In these cases, arc welding may be used on 8620 alloy steel. It is recommended that the piece itself be heated before and after welding, in order to strengthen the seams.

Related Articles

Properties & Uses for the 4340 Grades of Steel
What are the Types of Steel 4140?
The Mechanical Properties of JIS SCM 420H Steel
How to Tell the Difference Between Cast Iron & Cast...
Properties of Steel Types
Properties of Q345B Steel for Plate Material
How to Harden Steel With Motor Oil
Aluminum Hardness Classification
What Is Forged Steel?
Hot Rolled Steel Vs. Cold Rolled Steel
1018 Steel Properties
Differences Between Malleable Iron & Cast Iron
Steel Vs. Galvanized Steel Strength
Differences Between 52100 & E52100 Steel
The Effects of Cadmium Plating 304 Stainless Steel
Mechanical Properties of Mild Steel
How to Melt a Palladium Bullion
Properties of 1045 Steel
Types of Welding Metals