Induction Surface Hardening Research Articles

Technology and equipment for rational induction surface hardening of feed screws with recirculating balls

At the National Enterprise Carl Zeiss Jena (East Germany) an improved method of continuous sequential induction hardening of feed screws with highly accurate length was worked out.

Cooling by air and water mixtures during surface induction hardening

1. Apart from the water and air consumed, the cooling capacity of AWM during SIH depends to a marked degree on the distance h between the atmoizing device and the surface being cooled. 2. A cooling capacity equivalent to that of oil is exhibited by an AWM with the following parameters: Pair=0.2 MPa, Pwat=0.025 MPa, Qwat=25 liter/h with h=25 mm.

Self-tempering of stepped shafts in water-air hardening by a continuous step-by-step method

One of the advantages of water-air hardening is the possibility of conducting controlled self-tempering, which in surface induction hardening provides hardening without tempering in a furnace andexclamationthe creation of the optimum conditions for heat treatment in a single production line with full automation of the process. In addition, there are no hardening craccs on the treated parts. Investigation of the influence of the quenching and self-tempering times on the surface hardness was made on shaft model samples of 45 steel. The results of the inwestigations made show that a self-tempering time in the range from 10 to 60 seconds has little influence on the change in surface layer hardness. To obtain equal hardness in self-tempering (HRC 57-58), it is necessary to use higher temperatures than in furnace tempering. For 45 steel this difference is 75-85/sup 0/C with a tempering temperature up to 300/sup 0/C and 100-250/sup 0/C at higher temperatures. A comparison of the self-tempering and furnace tempering temperatures after hardening with a water-air mixture providing equal hardnesses of 45 steel are shown.

Strengthening isothermally hardened high-strength cast iron parts by surface induction hardening

Strengthening isothermally hardened high-strength cast iron parts by surface induction hardening

Effect of heat treatment on hardness of high-strength cast iron with spheroidal graphite

1. The heating rates generally used for surface induction hardening have no effect on the maximum hardness. However, the difference between the maximum and minimum microhardness increases with the heating rate. 2. In both bulk and surface isothermal hardening the hardness and microhardness decrease continuously with increasing temperatures of the cooling medium. At 350–400° the hardness decreases at a decreasing rate. 3. The hardness is higher after surface isothermal hardening than after bulk isothermal hardening at all isothermal holding temperatures generally used.

On a Certain Boundary Value Problem and Its Relevance in the Theory of Surface Induction Hardening

Progress in modern industrial technology is aided to a great extent by improved heat treatment of ferro-alloys, the most widely used basic construction materials in all kinds of machines and mechanisms. Wide use is now made of localized surface hardening of working regions of machine tool components following induction heating. This localization is achieved by the control of the frequency of an alternating current carried in an induction coil of shape suitable to the work piece so that the eddy current may be confined to the desired surface layer. In this paper is treated a two-dimensional boundary value problem associated with the surface hardening of a metallic cylinder. Under conditions which are not unduly restrictive, and which are usually satisfied in the physical situation, a representation theorem for the solution is proved. Some approximations to this solution are provided for numerical calculation of results. It is hoped that the method used will also be useful for analyzing other problems havin...

Induction Surface Hardening of Cast Iron

Induction Surface Hardening of Cast Iron

Heat-Checkingに関する研究（第1報）熱間工具鋼における実験と観察（その1）

Disk-like specimens and press mandrels made of 0.35% C, 5% Cr, 1.5% Mo, 1% Si hot-die steel were examined. The specimens were heated and cooled repeatedly by an induction surface hardening apparatus, and the mandrels were used for hot-pressing 0.3% C carbon steel. The formation and the propagation of the heat-checks was studied, and the results obtaind are as follows: (1) The formation of the heat-checks is affected by inter-granular oxidation of the surface in heat treated state. (2) The depth and the width of the checks distribute in exponential formula. (3) The heat-checks propagate gradually to the core and the distribution coefficient decreases in response to repetition of the heating and cooling cycle. (4) The heat-checks propagate mainly about the boundaries of the primary crystals.

高周波焼入の冶金学的研究（第5報）軸受鋼の高周波焼入におけるTemperingおよびMartemperingの影響ならびにその比較

高周波焼入の冶金学的研究（第5報）軸受鋼の高周波焼入におけるTemperingおよびMartemperingの影響ならびにその比較

鋳鉄の焼入に関する研究（第1報）鋳鉄の焼入硬度硬化深度および焼入歪について

In general,the hardening of cast iron has not so far been applied practically, because of its various troublesome factors,chemical compositions, microstructures and mechanical properties. Recently, Induction Surface Hardening has been used widely for steel. There are, however,few application to cast iron due to the difficulties accompaning its hardening. Therefore, the authors studied the hardening of cast iron, especially, Induction Surface Hardening to clarify these points and many phenomenas accompanying them. First, we investigated the hardness,hardened depth and strain of various cast irons. In these experiments, the higher input and the longer heating time were,the more Retained Austenite increased, subsequently, surface hardness dropped and the maximum hardness was displaced to inside layer (Fig. 1∼3). Quenching hardness was maximum at 850° in the case of ordinary quenching,but dropped in the range of high temperature, because of increased Retained Austenite (Fig. 4). Pearlite matrix is most desirable,for the combined carbon in matrix has remarkable influence upon the hardenability. As the size of graphite became smaller and more grobular, the quenching hardness of cast iron increased.From these points of view,Nodular Graphite Cast Iron treated with Mg has not only the best hardenability (Fig. 5∼8),but also the least strain (Fig. 9∼10).

高周波焼入の冶金学的研究（第4報）熱浴焼入の応用について

高周波焼入の冶金学的研究（第4報）熱浴焼入の応用について

高周波焼入の冶金学的研究（第1報）炭素鋼の硬度，歪及び残留応力に及ぼす炭素量の影響

高周波焼入の冶金学的研究（第1報）炭素鋼の硬度，歪及び残留応力に及ぼす炭素量の影響

高周波焼入の冶金学的研究（第3報）硬化深度と内部応力の関係について

高周波焼入の冶金学的研究（第3報）硬化深度と内部応力の関係について