US 2017/0362689 A1Published application

Ultrahigh-strength spring steel

AssigneeHyundai Motor Company

InventorsSung Chul CHA, Min Woo Kang, Hye Min Jo, Seung Hyun Hong

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Abstract

An ultrahigh-strength spring steel, used as steel for a vehicle engine valve spring may include 0.5 to 0.7 wt % of C, 1.3 to 2.5 wt % of Si, 0.6 to 1.2 wt % of Mn, 0.6 to 1.5 wt % of Cr, 0.01 to 0.5 wt % of Mo, 0.01 to 0.9 wt % of Ni, 0.5 wt % or less (excluding 0 wt %) of V, 0.5 wt % or less (excluding 0 wt %) of Nb, 0.3 wt % or less (excluding 0 wt %) of Ti, 1.0 wt % or less (excluding 0 wt %) of Co, 0.1 wt % or less (excluding 0 wt %) of B, 0.3 wt % or less (excluding 0 wt %) of W, 0.3 wt % or less (excluding 0 wt %) of Cu, 0.3 wt % or less (excluding 0 wt %) of Al, 0.03 wt % or less (excluding 0 wt %) of N, 0.003 wt % or less (excluding 0 wt %) of O, and a remainder of Iron (Fe) and inevitable impurities.

Claims8

Dependent claims

An ultrahigh-strength spring steel, suitable for use as steel for an engine valve spring of a vehicle, the ultrahigh-strength steel comprising:

0.5 to 0.7 wt % of Carbon (C), 1.3 to 2.5 wt % of Silicone (Si), 0.6 to 1.2 wt % of Manganese (Mn), 0.6 to 1.5 wt % of Chromium (Cr), 0.01 to 0.5 wt % of Molybdenum (Mo), 0.01 to 0.9 wt % of Nickel (Ni), 0.5 wt % or less (excluding 0 wt %) of Vanadium (V), 0.5 wt % or less (excluding 0 wt %) of Niobium (Nb), 0.3 wt % or less (excluding 0 wt %) of Titanium (Ti), 1.0 wt % or less (excluding 0 wt %) of Cobalt (Co), 0.1 wt % or less (excluding 0 wt %) of Boron (B), 0.3 wt % or less (excluding 0 wt %) of Tungsten (W), 0.3 wt % or less (excluding 0 wt %) of Copper (Cu), 0.3 wt % or less (excluding 0 wt %) of Aluminum (Al), 0.03 wt % or less (excluding 0 wt %) of Nitrogen (N), 0.003 wt % or less (excluding 0 wt %) of Oxygen (O), and a remainder of Iron (Fe) and inevitable impurities.

Dependencies are inferred from the claim text.