Case-hardening steels

Case-based reasoning CA. See Cyanuric acid Case-hardened steels Case hardening... 

Eig. 8. Illustration of the effect of nitriding on the wear resistance of a steel blasted with steel grit A, 300 HV steel B, 750 HV steel case hardened by carburizing and C, 1100 HV steel nitrided at 500°C for 60 h (17). HV = Vickers hardness. 

Soft, tough steel structural steel, case-hardened machine parts, screws... 

Example of use Mold frame steel Mold frame steel Case hardening steel, mold frame steel... 

In case hardening C and N are introduced into the iron by heating in a Nj —NH3 atmosphere or by immersing the steel in molten NaCN/Na2C03 at about 900"C. 

Fig. 4. Hardness—depth curve for case hardening of 0.6 wt % C steel by laser heating (7).

Case Hardening by Surface Deformation. When a metaUic material is plastically deformed at sufficiently low temperature, eg, room temperature for most metals and alloys, it becomes harder. Thus one method to produce a hard case on a metallic component is to plastically deform the surface region. This can be accomplished by a number of methods, such as by forcing a hardened rounded point onto the surface as it is moved. A common method is to impinge upon the surface fine hard particles such as hardened steel spheres (shot) at high velocity. This process is called shot... 

The complexity of the apparatus needed for ion implantation makes this method of case hardening of limited application. Further, the case depth is considerably lower than that produced by carburizing or nitriding. The depth of implantation of nitrogen in a steel is about 0.00006 cm (19), ie, so thin that it is difficult to measure the hardness profile by conventional microhardness measurements. 

H. E. Boyer, ed.. Case Hardening of Steel, ASM International, Metals Park, Ohio, 1987. 

Tool steels Hsted ki Table 13 are commonly used for temperatures above 175°C where hot hardness is requked. M50 tool steel has been widely used, for kistance, for the severe conditions encountered ki akcraft jet engine beatings (42). Figure 2 shows the superior hot hardness of M50 as compared with traditional through-hardened 52100 and case-hardened 4620 steels (39). 

Case harden Process of hardening the surface of a piece of steel to a... 

The major use of sodium cyanamide is in the production of sodium cyanide, a compound that is used extensively in preparing solutions for the electroplating of metals. Another use for NaCN is in extraction processes employed to separate gold and silver from ores as a result of their forming complexes with CN . Sodium cyanide, an extremely toxic compound, is also used in the process known as case-hardening of steel. In this process, the object to be hardened is heated and allowed to react with the cyanide to form a layer of metal carbide on the surface. 

Austenitic nitrocarburizing, case hardening by, 76 211 Austenitic stainless steels, 23 305-306 Austenitic steels, 23 243-244, 301 Austenitization, 23 284—285 Australia... 

Hardening, 1 528. See also Case hardening of melamine resins, 15 780-788 of steels, 16 196-199 Hard facing, 25 375 Hard fibers, 11 285... 

---