Showing papers on "Tempering published in 1982"

Steels, Microstructure and Properties

Abstract: Iron and its interstitial solid solutions * The strengthening of iron and its alloys * The iron-carbon equilibrium diagram and plain carbon steels * The effects of alloying elements in iron-carbon alloys * Formation of martensite * The bainite reaction * Acicular ferrite * The heat treatment of steels - hardenability * The tempering of martensite * Commercial Steels: New material to include Nanostructured Steels, Steels for the Energy and Automobile Industries * The embrittlement and fracture of steels * Stainless steel * Weld microstructures * Modelling of microstructure and properties *

Tempering of 2.25 Pct Cr-1 Pct Mo Low Carbon Steels

Abstract: The effect of carbon level on the tempering behavior at 700°C of 2.25 pct Cr-1 pct Mo steels having typical weld metal compositions has been investigated using analytical electron microscopy and X-ray diffraction techniques. The morphology, crystallography and chemistry, of each of the various types of carbides observed, has been established. It has been shown that each carbide type can be readily identified in terms of the relative heights of the EPMA spectra peaks for iron, chromium, molybdenum, and silicon. A decrease in the carbon level of the steel increases the rate at which the carbide precipitation reactions proceed, and also influences the final product. Of the carbides detected, M23C6 and M7C3 were found to be chromium-based, and their compositions were independent of both the carbon level of the steel and the tempering time. The molybdenum-based carbides, M2C and M6C, however, showed an increase in their molybdenum contents as the tempering time was increased. The rate of this increase became greater as the carbon content of the steel was lowered.

Optimization of Fe/Cr/C base structural Steels for improved strength and toughness

Abstract: Optimization of the composition and the heat treatments to provide a microduplex structure of dislocated-autotempered lath martensite and thin film retained austenite for good combinations of mechanical properties has been attained for Fe/Cr/C base steels Substituting 05 wt pct Mo to reduce Cr from 4 pct to 3 pct did not affect the microstructures nor the properties It was found that air melting as compared to vacuum melting does not cause deterioration of toughness in Mn containing alloys but does so in Ni containing alloys Tempered martensite embrittlement was confirmed as being due to the decomposition of retained austenite Further improvements in the fracture toughness are achieved by double heat treatments which provide grain refinement These alloys are considered to be very promising for structural applications

Tempering characteristics of a vanadium containing dual phase steel

Abstract: Dual phase steels are characterized by a microstructure consisting of ferrite, martensite, retained austenite, and/or lower bainite. This microstructure can be altered by tempering with accompanying changes in mechanical properties. This paper examines such changes produced in a vanadium bearing dual phase steel upon tempering below 500 °C. The steel mechanical properties were minimally affected on tempering below 200 °C; however, a simultaneous reduction in uniform elongation and tensile strength occurred upon tempering above 400 °C. The large amount of retained austenite (≅10 vol pct) observed in the as-received steel was found to be essentially stable to tempering below 300 °C. On tempering above 400 °C, most of the retained austenite decomposed to either upper bainite (at 400 °C) or a mixture of upper bainite and ferrite-carbide aggregate formed by an interphase precipitation mechanism (at 500 °C). In addition, tempering at 400 °C led to fine precipitation in the retained ferrite. The observed mechanical properties were correlated with these microstructural changes. It was concluded that the observed decrease in uniform elongation upon tempering above 400 °C is primarily the consequence of the decomposition of retained austenite and the resulting loss of transformation induced plasticity (TRIP) as a contributing mechanism to the strain hardening of the steel.

Method of making wrought high tension steel having superior low temperature toughness

Abstract: OF THE DISCLOSURE Due to increasing demands for steel to be used for construction such as buildings, pressure vessels, pipe lines or the like, various kinds of high tension steels, particularly steels suitable for welding have increasingly been developed. Heretofore, proposed methods of making such high tension steel have relied on so-called cold rolling and/or rolling followed by quenching and tempering, however, these conventional steels have suffered from drawbacks such as a tempering step indispensable after quenching, softening of welded zone and lack of uniformity in the metal structure in the direction of plate thickness. A compositional feature of the new method resides in addition of minor amounts of Ti and B along with Nb as contributing to grain refining or precipitation hardening elements in addition to limited amounts of other ingredients such as C, Si, Mn, S, Al and N. Further addition of at least one of V, Ni, Cu, Cr, Mo, Ca and REM also acts to improve the properties of the steel. The steel prepared to have the aforesaid composition is subjected to controlled heating, subse-quent rolling under prescribed rolling reduction ratio, temperature for terminating rolling and to a specified cooling rate. The steel plate thus processed has a structure having fine bainite grains alone or a duplex grain

Method of manufacturing products from high-strength alloys of the al-zn-mg-cu type and with transverse direction toughness

Abstract: 1. A method of producing hot extruded products of the type Al-Zn-Mg-Cu, which, in the treated state, has improved transverse characteristics, characterised by casting an alloy of the following composition (% by weight) : Si =< 0.08 Cu 1.0 to 2.0 Mg 2.1 to 3.5 Zn 7.2 to 9.5 Cr 0.07 to 0.17 Mn 0.15 to 0.25 Zr 0.08 to 0.14 Ti =< 0.10 Others each =< 0.05 Others total =< 0.15 Balance = Al and iron homogenizing the cast product in the range of temperatures of from 460 degrees C to the initial melting temperature of the alloy, hot extruding the product at a temperature of the order of 400 degrees C, optionally hot drawing the hot extruded product, putting the product into solution in the range of temperatures of from 460 to 490 degrees C, quenching the product in cold water (omicron =< 40 degrees C), cold working with a level of deformation (S - s/s) =< 10%, and a tempering operation : type T6 : that is to say, from 6 to 50 hours at from 115 to 150 degrees C, or type T7 : that is to say, from 3 to 24 hours at from 100 to 120 degrees C + 8 to 20 hours at from 150 to 170 degrees C, the longest periods of time generally being associated with the lowest temperatures.

Aluminum alloy reinforced with silica alumina fiber

Abstract: A process for preparing a fiber-reinforced metal composite material which comprises (1) combining an inorganic fiber comprising alumina as the main component and silica as the secondary component with an aluminum alloy containing at least one of copper, silicon, magnesium and zinc as the secondary component at a temperature of not lower than the melting point of said alloy to make a composite, (2) subjecting said composite to solid solution treatment, (3) quenching the treated composite and (4) optionally tempering the quenched composite at a temperature of from 100 to 250° C.

The Fracture Behavior of Quenched and Tempered Manganese Steels

Abstract: Manganese is present in all commercial low alloy steels, but its various effects on fracture are not completely understood. In this paper we report a study of the fracture behavior of quenched and tempered manganese steels. The steels were austenitized, quenched, and then tempered at temperatures between 150 °C and 500 °C. If the steel contained phosphorous, the fracture energy after all tempering treatments was very low and the fracture was intergranular. Tempering at temperatures near 350 °C produced especially low fracture energies because of the occurrence of intergranular tempered martensite embrittlement. Manganese does not increase the amount of phosphorous segregation during austenitization or tempering. However, it may increase the embrittling potency of phosphorous. If the steel did not contain a sufficient concentration of a grain boundary embrittling element such as phosphorous, the fracture mode was ductile microvoid coalescence. In this case manganese can be very important because it scavenges all of the residual sulfur in the alloy to form MnS precipitates. These are the initial sites of microvoid formation during ductile fracture, and their presence, especially in the form of elongated stringers, can lead to a reduced fracture energy.

Effect of Microstructure on Pitting and Corrosion Fatigue of 17-4 PH Turbine Blade Steel in Chloride Environments

Abstract: Depending on its heat treatment, 17-4 PH stainless steel may contain significant levels of reformed austenite and untempered martensite in a matrix of tempered martensite. Shot peening can...

Mossbauer surface study of a nitrogen implanted medium carbon steel

Abstract: The effect of nitrogen implantation on C40 medium-carbon steel is investigated by means of Mossbauer electron backscattering spectroscopy. Samples were implanted at various doses, after quenching from the austenitizing temperature and after quenching plus tempering, in order to detect the influence of the structure previous to the implantation. A different sequence of surface compound formation is observed in the two considered cases.

Metallurgical Characteristics of a Large Hydraulic Runner Casting of Type 13Cr-Ni Stainless Steel

Abstract: Increasing the size of type 13 Cr-Ni martensitic stainless steel castings with complicated cross sections results in difficulty in obtaining a uniform temperature distribution during thermal treatment, which in turn leadsto a critical condition for cracking, in addition to deterioration of impact properties due to slow cooling. Chromium carbides (Cr 2 3 C 6 ) precipitated by slow cooling through the austenite region at prior austenite or δ-ferrite grain boundaries cause an adverse effect on toughness, giving mosaic-like intergranular failure. Reducing silicon and carbon, along with the addition of molybdenum, improves toughness as the result of suppressing the Cr 2 3 C 6 precipitate. Toughness degradation due to slow cooling from the tempering temperature was considered to be associated with the decomposition of interlath-retained austenite and the solubility change of carbon. Lowering the silicon content and the addition of molybdenum lessen the toughness deterioration.

High-tension high-toughness steel having excellent resistance to delayed fracture and method for producing the same

Abstract: A high-tension high-toughness steel excellent in resistance to delayed fracture which consists essentially of 0.15 to 0.50% of C, up to 1.50% of Si, 0.20 to 1.50% of Mn, up to 2.00% of Cr, 0.0005 to 0.0030% of B, 0.005 to 0.10% of acid-soluble Al, up to 0.010% of P, up to 0.0020% of N, 0.010 to 0.050% of Ti and the balance iron and inevitable impurities, and has a tempered martensitic structure obtained by quenching and tempering.

Microstructures, mechanical properties, and electrical resistivity of rapidly quenched Fe-Cr-Al alloys

Abstract: By the rapid quenching technique, ductile supersaturated ferrite solid solution with high hardness and strength as well as unusual electrical properties has been found in Fe-Cr-Al ternary system. This formation range is limited to less than about 35 at. pct Cr and 23 at. pct Al. The ferrite phase has fine grains of about 10 μm in diameter. Their hardness, yield strength, and tensile fracture strength increase with increase in the amounts of chromium and aluminum, and the highest values reach about 290 DPN, 720 MPa, and 740 MPa. These alloys are so ductile that no cracks are observed even after closely contacted bending test. The good strength and ductility remain almost unchanged on tempering for one hour until heated to about 923 K where a large amount of Cr2Al compound begins to precipitate preferentially along the grain boundaries of the ferrite phase. The room-temperature resistivity increases with increasing chromium and aluminum contents and reaches as high as 1.86 μ Ώ m for Fe50Cr30Al20 alloy. Also, the temperature coefficient of resistivity in the temperature range between room temperature and 773 K decreases with increasing chromium and aluminum contents and becomes zero in the vicinity of 20 to 30 at. pct Cr and 15 at. pct Al. Thus, the present alloys may be attractive as fine gauge high-resistance and/or standard-resistance wires and plates because of the unusual electrical properties combined with high strength and good ductility.

The effect of heat treatments on the corrosion fatigue properties of 13 Pct Chromium Stainless Steel in 3 Pct NaCI Aqueous Solution

Abstract: The effect of austenitizing or tempering temperature on the corrosion fatigue properties of 13 pct chromium stainless steel was studied. Three pct NaCI aqueous solution was used as the corrosive environment, and the results were compared with the atmospheric fatigue properties. Strong influence of the tempering temperature on the S-N and FCP behavior of this blading material was found. The damage ratios (corrosion fatigue limit divided by endurance limit) of these various heat treated specimens became very low by this environment. Especially, extremely low corrosion fatigue strength of the specimen tempered at 600 °C was noticed. This microstructure was strategically used to clarify the reduction of pH inside the corrosion pits which were generally formed at the fatigue crack initiation sites. FCP data in the corrosive environment showed higher resistance than the atmospheric ones at the stress intensities below 18 MPa · m1/2, and which is opposite to the generally known influence of the corrosive environments. As for the fractographic feature, an appearance of the intergranular facets was especially noticed in NaCI aqueous solution environment. The fraction of this intergranular cracking was obtained as a function of the stress intensity factor.

Case hardening method for steel parts

Abstract: A method of case hardening surfaces of steel parts insures the presence of a relatively high percentage of untempered martensite within a case hardened depth of at least ten thousandths of an inch. The untempered martensite provides for a Rockwell C surface hardness in the range of 59 to 68, and promotes greater resistance to abrasion and deformation. The method also creates compressive stresses in the surface case hardened depth, and thus measurably enhances the fatigue life of the latter surface as a contact bearing member. The method includes the completion of all conventional metal removal operations on the part including finish machining steps prior to heat treatment thereof. In one preferred form, the method includes the steps of (1) completing all machining operations on the part, (2) carburizing the part to achieve a high surface carbon concentration, (3) direct quenching the part in oil by means resulting in retension of 10 to 30 percent austenite in the case hardened depth, (4) time tempering the part and (5) work hardening the part to transform a substantial portion of the retained austenite into untempered martensite, resulting in a case depth having a composition including at least 5 to 20 percent untempered martensite.

The role of nitrogen in the embrittlement of steel

Abstract: Nitrogen is one of the most common impurity elements to be found in steels. Previous work has shown that it is a potential grain boundary embrittler. In this paper we examine its role in both tempered martensite embrittlement and temper embrittlement. The basic composition of the steel used for this study was, in wt pct, 3.5 Ni, 1.7 Cr, 0.3 C, and 0.01 N. It was found that nitrogen could be very detrimental to mechanical properties but not as a grain boundary embrittler in the typical sense that P, Sn, and Sb are. Rather, nitrogen is almost always precipitated as nitrides and these second phase particles can induce low energy ductile fracture. The distribution of nitrides in the solid and the type of nitride present is dependent on the heat treatment. If a low austenitizing temperature is used, the nitrides in the steel dissolve and considerable nitrogen segregates to the grain boundaries. During an oil quench it reprecipitates at the boundaries, primarily as Cr2N. These nitrides cause low energy, ductile intergranular fracture. If a high austenitizing temperature is used, much less nitrogen segregrates so fewer nitrides precipitate during the quench. However, upon tempering the nitrogen does reprecipitate. At low tempering temperatures, small nitrides form both within the grains and along the grain boundaries. When these nitrides become sufficiently large, voids form around them as well as around the carbides during fracture. These small voids help link the large voids that form around oxide and sulfide particles and lower the energy for ductile fracture. After high temperature tempering treatments large nitrides and carbides form at the grain boundaries. These produce low energy, intergranular ductile fracture. These large grain boundary precipitates can also aid in brittle intergranular fracture by providing many more sites for nucleation of intergranular cracks when the boundary is weakened by another impurity element.

Heat treatment of forging

Abstract: PURPOSE:To manufacture forgings of stable quality at small heat consumption, by cooling a thick cylindrical steel product hot forged by upsetting of extrusion to a specified temperature, performing heat treatment of quenching and tempering starting from the temperature. CONSTITUTION:A thick cylindrical steel product is hot forged by upsetting or extrusion. The forging is once cooled to a temperature range of 390-250 deg.C to disappear substantially coase austenite in the structure, and the whole structure is changed to ferrite, pearlite and bainite. Then, it is heated from 390-250 deg.C to about 850 deg.C and quenched, and tempered at about 590 deg.C. A forging excellent in toughness having microstructure of very fine martensite is obtained. In this case, heating is made from 390-250 deg.C to quenching temperature, heat energy consumption is smaller compared with the case where heating is made from normal temperature to quenching temperature.

Factors affecting slip melting point of palm oil products

Abstract: The effect of different factors affecting the slip melting point of palm oil has been evaluated. The most important factor appears to be the difference in tempering temperatures. The influence of different tempering temperatures on slip point values is, however, dependent on the nature of the sample. For hydrogenated oils and for some high-melting palm stearins, tempering has no effect. For palm oil and palm olein, higher melting points were obtained when tempering at the higher temperatures in the range of 4–15 C. For some soft stearins, however, lower melting points were obtained at the higher tempering temperatures. These effects are investigated with differential scanning calorimetry and an explanation is offered, based on phase diagrams. A secondary effect on the slip melting point was the height of fat in the capillary tube. Effects of using different methods of determination are also shown. Collaborative trials on a standard testing procedure, AOCS Cc3-25, revealed the inadequacy for palm oil of the temperature range of 4–10 C specified in the procedure and its fractions. Strict adherence to a fixed tempering temperature produced better precision and reproducibility among laboratories. Tempering at 10±1 C is recommended.

Preparation of unnormalized high strength steel

Abstract: PURPOSE:To enhance the strength and the toughness of a rolled product, by a method wherein a steel piece with a specific composition subjected to hot molding rolling is again heated to an austenitizing temp. to be again subjected to hot rolling and the obtained rolled steel piece is subjected to tempering treatment. CONSTITUTION:A steel piece containing 0.02-0.15% C, 0.01-0.90% Si, 0.2-2.5% Mn, less than 0.025% P, less than 0.02% S, 0.001-0.01% N and 0.01-0.20% one or both of Nb and V and further containing one or more of Cu, Ni, Cr, Mo, Ti or B in a specific amount or containing one or more of Ca and Ce in a specific amount is heated to 1,200 deg.C or more to dissolve contained Nb, Al or V to form a solid solution and the treated steel is subjected to hot rolling to be processed into a steel plate, a steel pipe or die steel. Alternatively, the hot rolled steel may be further reheated to an austenitizing temp. to be subjected to hot rolling. The resulting steel is reheated on the way of cooling after hot rolling to be tempered at 400 deg.C-A1 point or below.

Fracture toughness of aisi M2 high-speed steel and corresponding matrix tool steel

Abstract: The influence of microstructural variations on the fracture toughness of two tool steels with compositions 6 pct W-5 pct Mo-4 pct Cr-2 pct V-0.8 pct C (AISI M2 high-speed steel) and 2 pct W-2.75 pct Mo-4.5 pct Cr-1 pct V-0.5 pct C (VASCO-MA) was investigated. In the as-hardened condition, the M2 steel has a higher fracture toughness than the MA steel, although the latter steel is softer. In the tempered condition, MA is softer and has a higher fracture toughness than M2. When the hardening temperature is below 1095 °C (2000 °F), tempering of both steels causes embrittlement,i.e., a reduction of fracture toughness as well as hardness. The fracture toughness of both steels was enhanced by increasing the grain size. The steel samples with intercept grain size of 5 (average grain diameter of 30 microns) or coarser exhibit 2 to 3 MPa√m (2 to 3 ksi√in.) higher fracture toughness than samples with intercept grain size of 10 (average grain diameter of 15 microns) or finer. Tempering temperature has no effect on the fracture toughness of M2 and MA steels as long as the final tempered hardness of the steels is constant. Retained austenite has no influence on the fracture toughness of as-hardened MA steel, but a high content of retained austenite appears to raise the fracture toughness of as-hardened M2 steel. There is a temperature of austenitization for each tool steel at which the retained austenite content in the as-quenched samples is a maximum. The above described results were explained through changes in the microstructure and the fracture modes.

A new low-carbon 16Cr-5Ni stainless martensitic cast steel

Abstract: A new low-carbon 16Cr-5Ni stainless martensitic cast steel (S+C 4405) is presented as an advancement of CA6NM with improved corrosion resistance, excellent ductility, less susceptibility to hardening cracks, and good weldability, filling the gap between CA6NM and CF8M. The chemical composition is balanced so that a homogeneous microstructure consisting of annealed martensite with small amounts of δ-ferrite and finely dispersed austenite is obtained after hardening and tempering. Because of limited δ-ferrite, the impact values obtained correspond to CA6NM, and limited austenite still allows yield strength values comparable to those of CA6NM. Due to its excellent ductility combined with good fabricability, the material is also suitable for cryogenic applications down to -200°C. Furthermore, favorable fatigue tests, and particularly test results in artificial seawater, show a remarkable improvement over CA6NM. Pitting- and crevice-corrosion tests by the International Nickel Co. multiple-crevice tetrafluoroethylene washer method suggest a corrosion resistance between that of CA6NM and CF8M and that this steel is suitable for seawater application in connection with cathodic protection. Stress-corrosion cracking in hydrogen sulfide-containing media was investigated according to the National Association of Corrosion Engineers Specification MR-01-75, and the resistance of 16Cr-SNi under sour-gas conditions was found to be superior to that of CA6NM. The castability of this alloy was found to be favorable and comparable to that of CA6NM. These characteristics are important for the following applications: offshore engineering, seawater desalination, chemical and petrochemical industries, shipbuilding, cryogenics, power generation, food industry, paper machine construction, and especially for pumps, compressors, fittings, centrifuges, waterturbines, and ship propellers.

Welding method of tempered type steel pipe

Abstract: PURPOSE:To obtain a welded steel pipe having high tensile strength and low temp. toughness, by tempering the same under limited conditions under submerged arc welding by a wire of the specific compsn. consisting of C, Si, Mn, Ni, Cu, P, S, Fe, etc. and a flux having specific basicity. CONSTITUTION:A steel pipe is welded by submerged arc welding by using a welding wire consisting of 0.05-0.15% C, =1.5, more preferably about 1.5-2.5 basicity B expressed by the equations. The welded steel pipe is quenched after heating to 900-1,100 deg.C and is then tempered for >=5min at 600-700 deg.C, whereby the welded steel pipe having the weld metal of high low temp. toughness wherein the Charpy transition temp. is about =50kg/mm. is obtd.

Structure and properties of low-carbon steel alloyed with boron and copper

Abstract: 1. Adding as much as 0.5% Cu to steel microalloyed with boron (as much as 0.003%) increases the solubility of boron in austenite and prevents precipitation of brittle boron-containing phase in austenite grain boundaries. This simplifies the melting procedure for steels with boron. 2. In steels with a higher boron content (0.003–0.005%) that are additionally alloyed with copper the borides are evenly precipitated within grains and in grain boundaries as small equiaxed inclusions. No boride phase was detected in cast or rolled steel with 0.003% B and 0.41% Cu. 3. Adding copper to steel with boron increases the stability of supercooled austenite somewhat and has no negative effect on the hardenability of the steel. 4. After heat treatment, steel with boron and copper has higher values of the strength and especially the fracture toughness as compared with steel with boron but without copper. The ductility of the steel with both additions is fairly high and approaches that of unalloyed steel as the tempering temperature is raised. Adding copper lowers the ductile-brittle transition temperature of steel containing boron.

The stress corrosion susceptibility of a quenched and tempered 12 pct crmov martensitic stainless steel

Abstract: The stress corrosion susceptibility of a martensitic 12 pct Cr 1 pct MoV stainless steel in alkaline chloride solution has been measured as a function of tempering heat treatment. The microstructures produced during tempering have been characterized by transmission electron microscopy and related to measured hardness values. In addition, scanning transmission electron microscopy combined with energy dispersive X-ray microanalysis has allowed the distribution of alloying elements within the microstructure to be examined. Electron energy loss spectroscopy was used to establish fully precipitate compositions, and the microanalysis results have been explained in terms of a diffusion controlled growth of grain boundary precipitates. The overall stress corrosion cracking susceptibility has been correlated with the development of chromium solute depletion profiles about prior austenite grain boundaries.

Hydrogen trapping in Ferrovac E-iron, mild steel and 4340 steel

Abstract: Hydrogen diffusion rates through Ferrovac E-iron, mild steel and 4340 steel have been studied using an electrochemical permeation cell. Thermal-mechanical processing included cold rolling and annealing and, in case of 4340 steel, quench and tempering. Apparent diffusion coefficients were determined from the slope of plots of log [(P-P0)√t] versus 1/t where P, P0 and t are the permeation rate at time t, the initial permeation rate and the time, respectively. Apparent diffusion coefficients are dependent on processing. Cold rolling and quenching produce trap sites that are annihilated during annealing and tempering, respectively. These traps are associated with lattice imperfections. In addition, the steels have trap sites at the interface between different phases. Both types of traps behave reversibly.

Manufacture of high toughness electric welded steel pipe

Abstract: PURPOSE:To manufacture an electric welded steel pipe whose weld zone has superior toughness in the manufacture of an electric welded steel pipe by electric resistance welding, by heating and cooling the weld zone under specified conditions, and tempering the whole pipe CONSTITUTION:An electric welded steel pipe is manufactured by a conventional method The weld zone of the pipe formed by electric resistance welding is heated to a temp in the temp range from the Ac3 transformation point preferably to about a temperature 200 degC higher than the Ac3 transformation point, and it is cooled at 15-30 degC/sec cooling rate from >=800 degC-<=500 degC The whole pipe is then tempered at 450 degC - the Ac1 transformation point Thus, an electric welded steel pipe having superior toughness at the weld zone as well as the base metal is manufactured with high work efficiency at a low cost

Production of sintered hard alloy tool

Abstract: PURPOSE:To prevent stress strain cracking and to obtain a sintered hard alloy tool joined to high strength, by subjecting the interface of both blank materials of a sintered head alloy and a steel stem part and a brazing metal to mutual diffusion then joining both blank materials by solid phase joining. CONSTITUTION:Steel for a stem part is formed roughly to the shape of a stem part 1, whereafter a brazing metal for joining consisting essentially of copper, Ni or silver is coated on the joint 3 surface thereof by electroplating, vapor deposition, etc. The steel for stem part and the brazing metal are then subjected to a diffusion treatment in order to increase the joint strength thereof and said treatment is accomplished at the same hardening temp. for the steel for stem part of 760-1,200 deg.C higher than said temp. Both parts are hardened simultaneously by the above-mentioned treatment, whereafter both materials are subjected to ordinary tempering. On the other hand, a blade part 2 made of a sintered hard alloy is formed roughly; thereafter, the brazing metal is diffused on the joint surface 3 thereof in the same way as for the stem part 1. Both joint parts are engaged and are subjected to joining by pressure at <=700 deg.C in a nonoxidative atmosphere.