Cold-working steel

Upon reheating cold-worked steel to the recrystallization temperature (- 450° C) or above, depending on composition, extent of cold working, and other variables, the original microstmcture and properties may be substantially restored. 

Cathodic treatment of steel parts in acids could be expected to contribute significantly to hydrogen embrittlement of the part if the steel has been previously heat treated to over 40 HRC. Cold-worked steel is susceptible at a lower hardness. Some work shows more embrittlement from the plating bath than from preplate treatments (36). 

It has also been noticed that thicker corrosion films form on the martensite phase in cold worked steels than on the untransformed matrix, and thicker films can be more brittle and aid crack initiation . ... 

Since the hardness test involves a substantial component of plastic deformation, hardness values are linked with tensile strength and not with yield strength when correlation between hardness and tensile properties are carried out. This appears to be a relationship between the hardness and tensile properties are carried out. There appears to be a relationship between he hardness of a metal and its tensile strength, but no general application has been found to exist. However, the following empirical relationship appears to hold fairly well for most steels, other than heavily cold worked steels or austenitic steels. 

Forged materials - primarily the groups of high-speed steels, cold work steels, and martensitic chrome steels. 

High Alloy Cold Work Steel D2 D3 T30402 T30402 X155 CrVMo 12-1 X210 Crl2 1.2379 1.2080... 

Medium Alloy Air Hardening Cold Work Steel A2 T30102 XI00 CrMoV5-l 1.2363... 

Oil Hardening Cold Work Steel 02 T31502 90 MnCrV8 1.2842... 

In very hard tool steels, for example, cold work steels tempered at low temperature, the wear resistance is originated mainly by hypereutectoid carbide which is not affected by hardening. These carbides are very small and evenly distributed and very hard (heavy-duty... 

K scc depends on metallurgical factors (it usually decreases as the strength of the steel increases, even though it also depends on the microstructure of the material, e. g. it is lower in quenched and tempered steel than in cold-worked steels) and on environmental factors (for instance, in alkaline environments and in the absence of chlorides, Kfscc so high that normal mechanical failure takes place before stress corrosion cracks can develop). 

Some of the reinforcing steel bar alloys are cold-worked steel epoxy-coated steel 30400 stainless steel 30453 stainless 31600 stainless 31653 stainless Duplex S31803. Table 5.9 shows the corrosion resistance of some steels. 

In Figure 17.12 one can see in coordinates In a-t the data for non-cold-worked steel and also for plastically deformed steel. The exponential dependence between the crack length and time of fatigue test is confirmed. 

According to our test data, these values are not more as yield strengthfy and 800 MPa for hot rolled and cold worked steel bars, respectively. The standardized second central moment of ultimate compressive stresses may be expressed as Sa c = Sosc — 0.105. 

The residual energy of a cold-worked steel as determined calorimetrically is 21 J/g. Calculate the increased tendency in volts for iron to corrode when cold worked. (Assume that the entropy change is negligible.)... 

Air-hardening, medium-alloy, cold-worked steels... 

FIGURE 4.83 Tempering curves for the cold work steel 1.2767 (45NiCrMo16) and the hot work steel 1.2343 (X37CrMoV5-1)... 

Clusters of impurities only decorate and therefore only stabilize the pre-existing dislocations network introduced by cold working because atmospheres do not have time to form on dislocations created under irradiation. Consequently, although the value of the stationary dislocations density in a cold-worked steel under irradiation is similar to the corresponding density in a solution annealed steel (Section 8.4.1), the properties and the structure of the lattices formed under irradiation are very different and therefore explain the poor resistance to swelling of a solution annealed 316Ti steel in which all dislocations were created under irradiation. 

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