| 摘要 |
<p>#CMT# #/CMT# Spring steel (I) comprises: 0.35-0.55 wt.% of carbon (C); 1.60-3 wt.% of silicon (Si); 0.20-1.50 wt.% of manganese (Mn); 0.10-1.50 wt.% of chromium (Cr); and at least one element comprising 0.40-3 wt.% of nickel (Ni), 0.05-0.50 wt.% of molybdenum (Mo), or 0.05-0.50 wt.% of vanadium (V), where the balance amount includes iron (Fe) and existing elements and impurities, and the following formulae (1) and (2) are satisfied: 0.400% >= C(%)+Mn(%)/6+Si(%)124+Ni(%)/40+Cr(%)/5+Mo(%)/4+V(%)/14 = 0.800% (1) and 0.540% >= C(%)+Mn(%)/6+Si(%)/25 = 0.670% (2). #CMT#USE : #/CMT# (I) is useful for producing spring, preferably coil spring (claimed). (I) is also useful in components of vehicle suspension systems, such as leaf springs, torsion bar springs and/or stabilizer bars. #CMT#ADVANTAGE : #/CMT# (I) has satisfactory corrosion fatigue strength or corrosion fatigue resistance. #CMT#INORGANIC CHEMISTRY : #/CMT# Preferred Composition: (I) includes each of Ni, Mo and V. At least one of the following properties of (a)-(c) is satisfied after quenching and tempering (I): (a) a number of corrosion endurance oscillating cycles is at least 45000; (b) a Charpy impact value is at least 80 J/cm 2>; and (c) a delayed fracture strength is at least 910 MPa. (I) has a Rockwell hardness of 53-56. Preferred Components: The following formulae (3)-(5) are satisfied: 1.20%>= Si(%)-0.46C(%)-1.08Mn(%) (3), where the lower limit of the formula (3) is 1.35%, 159C(%)-Si(%)+8Mn(%)+12Cr(%) = 84% (4) and 6C(%)-Si(%)-0.3Mn(%)+1.4Cr(%)= 1.2% (5). The quantity C, Si and Mn is 0.45-0.50% (preferably 0.46-0.49%), 2-2.50% and 0.40-0.50%, respectively. #CMT#EXAMPLE : #/CMT# Typical composition comprised of (in wt.%): carbon (0.46) ; silicon (2.19); manganese (0.70); chromium (0.19); phosphorus (0.004); sulfur (0.005); nickel (0.30); copper (0.18); molybdenum (0.18); titanium (0.023); and boron (0.002).</p> |
