6.   Molybdenum Steel:

       It contains  C 0.35% and Mo 0.76%

• Molybdenum steel, when heat-treated, produces a structural steel which has increased elastic limit without correspondingly decreased ductility.
• It improves hot hardness and strength of steel.
• This type of steel is not effected by temper brittleness
• Molybdenum steels are used for making aircraft landing gear, coil and leaf springs, fuselage, pressure vessels and transmission gear etc.

 7.    Chrome-Molybdenum Steel:

        It contains  C 0.35% , Cr 1.06% and Mo 0.36%

•  It is easy to roll and drawn into tubes, to fabricate, and to weld, so that it is very popular for airplane structural parts

 8.    Chrome Steel:

         It contains  C 0.36% and Cr 0.57%

• It intensifies the effect of rapid cooling on steel. Therefore chromium is used only in steels which are to be heat-treated.
• Chromium forms carbides and gives high hardness and good wear resistance.
• It increases tensile strength and corrosion resistance of low alloy steel

 9.     Manganese Steel:

         It contains  Mn 1.6-1.9% , C 0.18 - 0.48%, Si 0.2- 0.35%, S and P less than 0.40% each.

• It increases hardness and tensile strength.
• It increases resistance to abrasion.
• Manganese steels are used for making power shovel buckets, grinding and crushing machinery, railway tracks etc.

10.    Tungsten Steel:

          It contains 2% tungsten, 1.7% chromium and 0.5% carbon.

• This type of steel is basically used for making cutting tools.
• Tungsten forms carbides and prevents softening of the alloy at high temperature
• Tungsten steel may contain upto 15% tungsten. Tungsten is used for making high speed cutting tools and permanent magnets.

11.    Vanadium Steel:

• Vanadium is one of most powerful scavengers added to liquid steel for removing oxygen.
• Vanadium increases the strength and hardness of the metal.
• Vanadium produces very fine grain structure
• Vanadium is used together with chromium and other alloying elements when high strength and anti-fatigue properties are essential, as in springs, gears, shafts and heavy forgings.

12.     Cobalt Steel:

• It is used where high frictional heats are developed . Cobalt imparts additional red hardness to steel and cutting ability of tool is maintained at elevated temperatures.