Name
SKL12 Rail Clip
Type
Skl clip (skl1,skl3,skl12,skl14)
E clip (e1809, e2006,e2007,e2009,etc) 
 Or the type by customers' drawings
Material
60Si2MnA
60Si2CrA
55Si2Mn
38Si7
Chemical composition(%)
C:0.56-0.64, Mn:0.60-0.90, Si:1.60-2.00, Cr:≤0.35, P:≤0.03, S:≤0.03
C:0.56-0.64, Mn:0.40-0.70, Si:1.40-1.80,Cr:0.70-1.00 P:≤0.03, S:≤0.03
C:0.52-0.60, Mn:0.60-0.90, Si:1.50-2.00,Cr:≤0.35  P:≤0.03, S:≤0.03
C:0.35-0.42, Mn:0.50-0.80, Si:1.50-1.80, P:≤0.03, S:≤0.03
Hardness
For e clip: 44-48HRC
For skl clip: 42-47HRC
Fatigue life
for Dia.18 is 3 millions cycles without breaking  
for Dia.20 is 5 millions cycles without breaking
Surface
plain (oiled), Oxide black, color painting, HDG, Zinc Plating...
Standard refers
DIN17221, BS970, GB/T1222