10-09-2016, 03:16 PM
1454494257-WORDFILEP15LIFEIMPROVEMENTOFHADFIELDMANGANESESTEEL.docx (Size: 8.32 MB / Downloads: 6)
Abstract
• This project report is related to Hadfield Mn steel & also Hi-Cr steel.
• This report contains the manufacturing process, heat treatment cycle, composition, properties & applications of Hadfield Mn steel & Hi-Cr steel.
• This report also covers the different factors which affect in life improvement of Hadfield Mn steel & Hi-Cr steel.
• In this report the improving life of Hadfield Mn steel done by applying two different Heat treatment cycles.
• The effect of first stage heat treatment process on microstructure, chemical composition and hardness of austenitic Manganese steel & Hi-Cr steel has been studied. Samples of steel were taken & checked their hardness, chemical composition & microstructure & then done heat treatment on it & again checked their hardness, chemical composition & microstructure. It was found out that heat treated sample’s carbide particles dispersed on austenite matrix. This led to an increase in the hardness.
• The effect of second stage heat treatment process (precipitation hardening) on microstructure and hardness of Austenitic Manganese Steel has been studied. Samples of the steel were machined, autenitized at 10000C and held for one hour, water quenched and then aged at different temperatures and holding times. The samples were artificially aged at 600oC and 700oC and were held for one, two and three hours. Microstructures and hardness values of the samples were taken. It was found out that sample aged at 700oC for 2 hours has its carbide particles finely dispersed on the austenite matrix. This led to an increase in the hardness.
MANGANESE STEEL :-
DEFINATION: - Generally steel having about 1 to 1.7%Mn and 0.8%C is called MANGANESE STEEL.
Manganese amount between 2 and 10% imparts brittleness to steel.
Mn in the range 1.65 to 1.90% is added to improve tensile strength, hard ability and hot workability of steel.
The presence of manganese also enhances the response of steel to heat treatment.
If the manganese content is increased to 11 to 14% in steel containing 1 to 1.2%C a tough, wear resistant product may be obtained after suitable heat treatment, this material is known as HADFIELD MANGANESE STEEL.
What is the Hadfield manganese steel?
• Hadfield’s manganese steel was invented by Sir Robert Hadfield in 1882.
• If the manganese content is increased to 11 to 14% in steel containing 1 to 1.2%C a tough, wear resistant product may be obtained after suitable heat treatment, this material is known as HADFIELD MANGANESE STEEL.
• it exhibited high toughness, high ductility, high work Hardening ability and excellent wear resistance
HEAT TREATMENT CYCLE FOR HAD FIELD Mn STEEL
1. Raise the temperature from 200 to 700 Oc @ 120 per hour.
2. Hold at 700 c for 3 hours.
3. Raise the temperature from 700 to 1100 @ 120 per hour.
4. 1 inch/1 hr + 1 hr =soaking time of individual castings.
5. After soaking, water quench immediately within 40 sacs inside the agitated water.
6. Water temperature should not raise above 40 deg cent and circulate cooling water.
PROPERTIES
• yield strength between 50,000 psi (345 MPa) to 60,000 psi (414 MPa)
• The modulus of elasticity is 27 x 10 psi. (186 x 10 MPa)
• high wear resistance ,toughness ,hardness and tensile strength.
• The ultimate tensile strength of AMS varies but is generally taken as 140,000 psi (965MPa).
• The fatigue limit for manganese steel is about 39,000 psi. (269 MPa).