0.1% or dead mild steal, was used in the manufacturing of wheel rims, in the late 19th century. This form of steel was popular at this period for a few reasons including its soft and ductile tendencies, and its mass availability in the 1880’s. Its composition included iron and carbon, and was manufactured by being cut into strips, heated and then shaped and forge welded by a blacksmith. The hot metal would then shrink onto the cold rim. Its 2 microstructure phases are ferrite and cementite and its equilibrium structure contains equiaxed grains of ferrite and small grains of pearlite.
0.3% carbon steel was one of the more versatile steels of the 20th century. This particular alloy was first used in the 1920’s in brake nuts and bolts. It was the chosen steel as it was readily available and its properties, which include malleable, ductile and tough, due to its ferrite matrix. It was made into the nuts and bolts by being hot rolled into bars, forged into shape, thread and machine formed. It was an easily forming metal which made it popular for brake springs.
Both 0.3% carbon steel, and 0.6% carbon steel was used in brakes springs in the 1950’s, this still is known as medium carbon steel. This was a very tough steel and was easily machined when heat treated. It was also good for springs because of its resilience, high elasticity and failure to be corroded by brake fluid. The brake springs were manufactured by being hot drawn into wire shape, then harden and temper the spring. The equilibrium structure of medium carbon steel is small equiaxed grains of ferrite, and large grains of pearlite. Its microstructure phases contained ferrite and cementite.
0.8% carbon steel was majorly used in one application in the mid-20th century, cable wire. Again this steel was readily available and in high production in this period, hence why it was used. It produced good toughness and high tensile strength and was easily heat treatable. The wire was...