Shock Resisting Took Steels

Question 1

What contributes to the alloys increase shock resistance?

Answer 1

1st - Toughness
2nd - Hardness
It is therefore necessary to have lower carbon contents than other tool steels to improve impact strength.

Question 2

What are applications of shock resisting tool steels?

Answer 2

•For tools where repeated high impact stresses are encountered

•Tool industry (forging dies, punches, chisels, hammers, hot heading dies and gripper dies)

•Cutting Tools: shear blades

Question 3

What are characteristics of shock resisting tool steels?

Answer 3

•High impact resistance
•Excellent toughness at high strength levels
•Good wear resistance
•High hardenability and softening resistance

Question 4

What is typical S7 heat treatment?

Answer 4

1. ANNEALING - heating slowly and uniformly 815-845 C, furnace cooling at 510 C at a rate of 8-15 C/hr.
2. STRESS RELIEVING - warming to 650 C
3. HARDENING
   Preheating: warming to approx. 650-700 C, holding for 20 mins per 25mm.
   Austenitzing: heating to approx. 925-960 C, holding for 20 mins per 25mm.
   Quenchant: by oil
4. TEMPERING: 150-200 C, holding for 30 mins per 25mm. Air cooling, hardness min. HRc 56.