Steel Wire for Cold Formed Spring
Spring Steel wires are used for manufacturing tension and compression coil springs which are subjected to static or low-to-high dynamic stresses and even for Impact loaded springs e.g. Motorcycle Shockers, Car Seats etc. Aarti Steels Limited is in a position to manufacture spring wire from 0.34mm to 8 mm in diameter. The present manufacturing capacity of such wires being 5,000 METRIC TONES PER YEAR. The basic properties of spring steel wire are given hereunder :

Chemical Composition :

Grade Carbon % Silicon % Manganese % Sulphur % Phosphorus %
1 0.50-0.60 0.10-0.35 0.50-0.80 0.05 max 0.05 max
2 0.60-0.75 0.10-0.35 0.50-0.80 0.05 max 0.05 max
3 0.65-0.80 0.10-0.35 0.60-0.90 0.05 max 0.05 max
 
Size and SizeTolerance :

Dia Range (in mm) Gr.I Gr.II Gr.III
0.28-0.29 +0.015 +0.010 +0.010
0.30-0.84 +0.02 +0.015
+0.010
0.85-1.40 +0.03 +0.020 +0.015
1.50-1.95 +0.04 +0.030 +0.020
2.00-3.30 +0.05 +0.035 +0.025
3.35-5.00 +0.06 +0.040 +0.030

Tensile Strength :

Dia Range (in mm)
Tensile Strength (in N/mm2)
Gr.I Gr.II Gr.IIi
0.28 - 2060 2460
0.30 1720 2060 2460
0.32 1710 2050 2450
0.34 1710 2050 2450
0.36 1700 2040 2440
0.38 1700 2040 2430
0.40 1700 2040 2430
0.43 1690 2030 2420
0.45 1680 2020 2410
0.48 1680 2020 2400
0.50 1670 2010 2390
0.53 1660 2000 2380
0.56 1660 2000 2370
0.60 1650 1990 2360
0.63 1640 1980 2340
0.65 1640 1980 2330
0.70 1630 1970 2320
0.75 1620 1960 2300
0.80 1610 1950 2280
0.85 1600 1930 2260
0.90 1590 1920 2250
0.95 1580 1910 2250
1.00 1570 1900 2240
1.05 1560 1890 2210
1.10 1550 1880 2190
1.20 1540 1860 2170
1.25 1530 1850 2140
1.30 1520 1840 2130
1.40 1500 1820 2110
1.50 1490 1800 2100
1.60 1470 1780 2080
1.70 1460 1760 2050
1.80 1440 1750 2030
1.90 1430 1730 2010
2.00 1420 1720 1990
2.10 1410 1700 1960
2.25 1400 1680 1940
2.40 1380 1660 1910
2.50 1370 1640 1890
2.60 1360 1620 1860
2.80 1340 1600 1840
3.00 1320 1570 1830
3.20 1310 1550 1790
3.40 1290 1530 1760
3.60 1270 1510 1750
3.80 1260 1490 1720
4.00 1250 1480 1700
4.25 1250 1460 1680
4.50 1230 1440 1660
4.75 1210 1420 1620
5.00 1190 1390 1600

Note : 1 M Pa = 1 MM2 = 1 MN/M2 = 0.102 kgf/mm2

Reduction in Area/Torsion :

Dia (in mm) % Reduction in Area Minimum Torsion No. on L = 100 x dia in mm or 500 mm max.
0.39-0.49 - -
0.50-1.05 - 25
1.10-3.00 40 22
3.05-3.90 40 20
4.00 35 20
4.10-5.00 35 18

Wrapping Test :  This test is applicable to wires of 0.50 mm or lesser diameter. Approx 500 mm long wire is tightly wound closely on an arbor equal to 3 times the diameter of the wire and then stretched to 5 times the original length of the coiled spring before being released. The test spiral shall show a uniform pitch.

Coil dimension/Coil weight :

Wire dia (in mm )
Coil Dimensions (in mm)
I.D. (mm) O.D. (max.)
Approx. Coil weight (kgs.)
0.28 to 0.34 175 360 3 to 10
0.35 to 0.36 170 400 10 to 50
0.78 to 1.35 250 430 70 to 80
1.40 to 2.80 550 700 100 to 180
2.85 to 5.00 700 900 100 to 200

Packing : Coils are coated with Rust-preventive chemical & packed in polythene & Hessian.