Hardening and Tempering. If steel isheated to a high temperature, bright or cherry red, and thenquenched in oil or water, the atoms of iron and carbon re-arrangethemselves in a formation which give the metal a very hardand brittle property. This process is known ashardening..
Considering this, how do you harden steel?
To harden steel, start by heating the metaldirectly with a blow torch until it turns a cherry red color. Then,use a pair of tongs to carry the steel to a container filledwith water or vegetable, and submerge the hot metal in theliquid.
Subsequently, question is, how do you harden steel with motor oil? The carbon in the motor oil bonds with the toplayer of red-hot steel molecules and forms a tough outercovering on the steel. One last step is necessary, however,before your hardened steel is ready to work with. Heat thesteel using a torch or a furnace with bellows. Continueuntil the steel glows red-hot.
Likewise, can spring steel be formed?
Spring steel is hardened carbon steel, notso special. But due to the hardening it remain its form. Ifyou want to bend it you have to have to heat it to red glowing whenit will loose its hardness. So you can not just bendit, as it will spring back.
Why does quenching increase hardness?
Hardened materials are usually tempered or stressrelieved to improve their dimensional stability and toughness.Steel parts often require a heat treatment to obtain improvedmechanical properties, such as increasing increase hardnessor strength. Quenching "freezes" the microstructure,inducing stresses.
Related Question Answers
What temperature does steel harden at?
As the steel is heated above the criticaltemperature, about 1335°F (724°C), it undergoes aphase change, recrystallizing as austenite. Continued heating tothe hardening temperature, 1450-1500°F (788-843°C)ensures complete conversion to austenite.Why annealing is done?
Annealing is a heat treatment process whichalters the microstructure of a material to change its mechanical orelectrical properties. Typically, in steels, annealing isused to reduce hardness, increase ductility and help eliminateinternal stresses.What oil do you quench steel in?
The two most common food grade oils used in this processare peanut and canola oil. Both of these oils havehigh flash points which is good for the quenching process.You will need to preheat these oils to slightly highertemperatures when compared to commercial quenching oils (120- 130 degrees Fahrenheit).Can I Harden mild steel?
"Mild steel" can be hardened to a degree.It's surprising how hardenable "mild steel" is if the rateof cooling is high enough.Why is hardened steel brittle?
Untempered martensite is a strong, hard, brittlematerial. The stronger and harder it is, the more brittle itis. The strength and hardness is a due to elastic strain within themartensite, which is a result of too many carbon atoms being in thespaces between the iron atoms in themartensite.What is spring steel made of?
These steels are generally low-alloy manganese,medium-carbon steel or high-carbon steel with a veryhigh yield strength. This allows objects made of springsteel to return to their original shape despite significantdeflection or twisting.Does heating Steel weaken it?
Untempered steel is very hard but too brittle formost practical applications. The process involves heatingsteel to a lower temperature to reduce some of the excesshardness. The metal is then allowed to cool in still air whichresults in a tougher and less brittle steel.Can spring steel be welded?
You shouldn't even weld near your springs, letalone on them. Springs don't stand well to heat, since heat causessprings steel to de-carbonize and lose tensile strength,making the area around the weld brittle like a cheap pencil.As the name implies, this creates stress, which causes a weaknessin the steel.Is spring steel magnetic?
Carbon steel is highly magnetic and istypically blue in color. Stainless Steel 301 is capable ofattaining high tensile strength and ductility by cold working. Itis not hardenable by heat treatment. Type 301 is essentiallynonmagnetic in the annealed condition and becomes magneticwith cold deformation.Does annealing increase toughness?
In order for the annealing process to occurcorrectly, this cooling process must be slow in steels and otherferrous metals. Annealing can increase ductility andalleviate internal stresses that contribute to brittleness.Annealing can also increase toughness and homogeneityof metals. 
