Application of S1:
S1 tool steels are mainly used for Mandrel drawing steel tube. Medium temperature applications include forging, forming and die, punching, punching and reduce death. Other applications include shear blade working medium temperature including flying shear blades., cold taps, reamers, collets, cutting hobs, strip slitting cutters, trimmer dies, tube expander rolls, plastic moulds and woodworking knives ature.
Introduction of S1:
Shock-resisting tool steels are designated as group S steels according to the AISI classification system. S1, S2, S5, S6, and S7 are the types of shock-resisting tool steels. The hardenability of group S steels can be controlled by varying their composition instead of adjusting the melting procedures and grain size. These steels can obtain optimum hardness at higher austenitizing temperatures. The tempering resistance of group S steels can be enhanced by addition of silicon, which also forms a microstructure to resist distortion in tempered conditions.
AISI S1 Chemical Composition:
Element Content (%)
C 0.40-0.55
Mn 0.10-0.40
Si 0.15-1.20
Cr 1.00-1.80
Ni 0.3
Mo 0.5
V 0.15-0.30
Cu 0.25
P 0.03
S 0.03
W 1.50-3.00
AISI S1 Mechanical Properties:
Properties Metric Imperial
Hardness, Rockwell C (air cooled from 899°C, 30 mins) 54.5 54.5
Hardness, Rockwell C (air cooled from 927°C, 30 mins) 56 56
Hardness, Rockwell C (air cooled from 982°C, 30 mins) 56.5 56.5
Modulus of elasticity 207 GPa 30000 ksi
Charpy impact (V-notch; oil quenched from 954°C; 149°C temper temperature) 10.8 J 8.00 ft-lb
Charpy impact (V-notch; oil quenched from 954°C; 625°C temper temperature) 29.8 J 22.0 ft-lb
Machinability (1% carbon steel) 70.0 - 75.0% 70.0 - 75.0%
Poisson's ratio 0.27-0.30 0.27-0.30
AISI S1 Tool Steel Other Designation:
AFNOR 55 WC 20
DIN 1.2550
UNI 58 WCr 9 KU
ASTM A681
FED QQ-T-570
SAE J437
SAE J438
UNS T41901
ASTM A681
DIN 1.2542
S2 Tool Steel Fabrication and Heat Treatment:
Forging
S1 tool steels are uniformly preheated at 1000°C (1832°F). These steels are then forged at temperatures ranging from 800 to 1000°C (1472 to 1832°F). This process is followed by cooling in a furnace to avoid stress.
Annealing
Annealing is carried out in S1 tool steels by uniformly heating the steels to 770°C (1418°F) followed by equalization. These steels are then cooled in the furnace.
Stress Relieving
S1 tools steels are heated up to 700°C (1292°F) before hardening, equalized, and then slowly cooled in order to remove stresses during heavy machining operations.
Hardening
S1 tools steels are preheated to 650°C (1202°F) and soaked. They are then continuously heated to the final temperature that ranges from 900 to 950°C (1652 to 1742°F). Finally, the steels are quenched in oil.
Martempering
Martempering is performed in the case of S1 tool steels as an alternative procedure for hardening. This is carried out in a salt bath equipment.
Tempering
S1 tool steels are tempered
