Induction hardening

A wide range of shapes can be induction hardened and a system for quenching can be incorporated into the coil assembly. The process can be automated to harden components in an essentially continuous manner. The case depth is controlled by the coil design, frequency, power, and time of apphcation. 

Typical hardness distribution curves obtained by induction hardening are available (5). Case depths of ca 0.05—0.5 cm are commonly obtained. 

Figure 4 shows a typical hardness distribution (7). The case depth is considerably less than that for flame and induction hardening. The case has a high compressive residual stress, which improves the fatigue properties (8). 

T. H. Spenser and co-workers. Induction Hardening and Tempering, American Society for Metals, Metals Park, Ohio, 1964. 

Induktions-hMrten, n.(Metal.) induction hardening. -ofen, m. induction furnace, -rolle, -spule,/. induction coil, -strom, m. induction current, -vermogen, n. inductive capacity, -wirkung, /. inductive effect, -zeit, /. period of induction. 

Figure 12-7. Piston rods. Precision-manufactured rolled threads and induction hardening provide high fatigue strength and long life in heavy duty service. Standard rod material is AISI 4142 carbon steel other materials are available as required. Tungsten carbide coatings are also available for maximum surface hardness. Pistons are locked securely onto the rods. For higher pressure, smaller bore cylinders, the piston may be integral with the rod. (Used by permission Bui. 85084, 1992. Dresser-Rand Company.)...

The two basic types are (1) through hardenable, and (2) surface harden-able. Subcategones of surface hardenable alloys include carburizing alloys, flame and induction-hardening alloys, and nitriding alloys. 

Determination of residual stress of a failed component is one of the most important steps in failure analysis. The determination of residual stress is useful when failed components experience stress concentration, overload, distortion or the formation of cracks in the absence of applied loads, subjected to corrosive environments as in stress corrosion, mechanical or thermal fatigue due to cyclic loading, or when faults in processing such as shot peening, grinding, milling and improper heat treatment such as stress relief, induction hardening, thermal strains, exposure temperature are involved. 

Fig. 25 Microstructure of L3/CVD TiN/induction hardened (a) substrate, 3% alcoholic HNOg etch and (b) surface, 3% alcoholic HNOg etch.

Induction hardened Heavy case depths with good capacity for contact loads, good benging fatigue resistance and fair dimensional control... 

Flame or induction hardened. (2) Trademark of La Salle Co. (3) Trademark of Joseph T. Ryerson Son Inc. (4) Nitrided. (5) Usually improved by hardsurfacing. (6) Trademark of Armco Steel Corp. (7) Trademark of Crucible Specialty Metals. (8) Trademark of Huntington Alloys Inc. (9) Trademark of Cabot Corp. 

Wan] Wang, W.-R, Effect of Alloying Elements and Processing Factors on the Microstracture and Hardness of Sintered and Induction-Hardened Fe-C-Cu Alloys , Mater. Sci. Eng. A, 402(1-2), 92-97 (2005) (Experimental, Morphology, Phys. Prop., 26)... 

Ti5Al-2.5Fe Ball-in-socket 0.9% NaCl UHMWPE socket 100-2500 N Friction moment 0.5-1.0 Nm (oxidized, induction hardened) Zwicker et al, 1985... 

Heat treatment steels, intended for hardening and induction hardening, are usually alloyed with chromium, nickel and molybdenum, which improve the deep hardening. 

Cast or fabricated steel cast steel sprockets have cast teeth, whereas fabricated steel sprockets have flame-cut teeth. Both are designed to snstain heavy torque and shock loads. For the most demanding work in highly abrasive conditions, the teeth are flame or induction hardened. 

Surface hardenability - laser hardening, flame hardening or inductive hardening,... 

Induction hardening is a versatile heating method that involves placing a steel part in the magnetic field generated by high-fi equency alternating... 

Table 2 Comparison of flame- and induction-hardening processes...

Laser/EB harden Carbonitride/caiburize/cyanide Induction-hardened steels Flame-hardened steels... 

Induction-hardened 0.4% C steel Sluny/sinler fanned ceramic Nitrided 316 stainless steel... 

---