143 results about "Maraging steel" patented technology

A golf club head includes a front member, a rear member and a neck connected together to form a housing. The front member, which is made of a flexible material, such as aluminum alloy, stainless or Maraging steel, has a face and an annular wall projected from a back of the face to form a cup-like member, wherein the wall has a connecting portion at a distal end thereof, and a length of the wall is identical to or greater than 8 mm and a thickness of the wall is identical to or less than 2 mm. The rear member, which is made of a light metal, such as magnesium alloy or aluminum alloy, has a connecting portion to engage the connecting portion of the front member. The neck is fixed on the rear member.

A pencil-type glow plug for a self-igniting internal combustion engine is described. The pencil-type glow plug includes a plug body in which a combustion chamber pressure sensor is integrated, and a bar-shaped heating element that protrudes out from the plug body at one end, into the combustion chamber of the internal combustion engine. A force-measuring element of the combustion chamber pressure sensor is accommodated behind the heating element, which moves axially under the influence of force. The force-measuring element is sealed against combustion chamber gases by a steel diaphragm made of a stainless precipitation-hardened maraging steel.

The invention discloses a forming method of a maraging steel mold adopting selective laser melting. A three-dimensional structure of the mold is designed firstly by using three-dimensional design software such as Solidworks, ProE and Ug; and then the three-dimensional mold is subjected to slicing layering and route planning treatment, data are guided into a selective laser melting device, reasonable technical parameters are set, and the mold with a complex cooling channel is formed at a time. The mold formed by the method has the advantages of being high in compactness, few in internal defect, high in forming efficiency and high in free degree on the follow-up forming cooling channel. According to the forming method of the maraging steel mold adopting selective laser melting, the production period of the mold is effectively shortened, forming efficiency is high, external disturbance is small, the compressive property and production efficiency of the mold are remarkably improved, and meanwhile manufacturing cost is greatly reduced. After the directly-formed mold is subjected to solution and aging treatment, hardness and strength of the mold are remarkably improved, and the using requirements of the mold are met.

A pencil-type glow plug for a self-igniting internal combustion engine is described. The pencil-type glow plug includes a plug body in which a combustion chamber pressure sensor is integrated, and a bar-shaped heating element that protrudes out from the plug body at one end, into the combustion chamber of the internal combustion engine. A force-measuring element of the combustion chamber pressure sensor is accommodated behind the heating element, which moves axially under the influence of force. The force-measuring element is sealed against combustion chamber gases by a steel diaphragm made of a stainless precipitation-hardened maraging steel.

The invention discloses aluminum-strengthened maraging steel and a preparing method of the aluminum-strengthened maraging steel. The aluminum-strengthened maraging steel comprises, by weight percent, 0.01% to 0.2% of C, 6% to 24% of Ni, not larger than 6% of Mo, 0% to 4% of Mn, 0.5% to 6% of Al, 0% to 12% of Cr, 0% to 1.5% of Nb, 0% to 4% of Cu, 0% to 3% of W, 0.0005% to 0.05% of B and the balance Fe and inevitable impurities. Smelting is carried out according to ingredient compositions, and through forging, solid solution treatment and cold rolling heat treatment processes, the maraging steel is prepared, wherein the structure of the maraging steel is uniform, a high-density B2-NiAl intermetallic compound is a main strengthening phase of the maraging steel, and micro carbide and nanoclusters conduct joint strengthening on the maraging steel; and the maraging steel shows the excellent mechanical property, the tensile strength can reach 2.2 GPa. In addition, the main strengthening phase NiAl and a base body are in a coherent relationship, and the elasticity modulus and the base body are basically consistent.

The invention relates to the technical field of martensite aged steel and preparation methods thereof and particularly relates to metal powder injection molded high-strength martensite aged steel and a preparation method thereof. The metal powder injection molded high-strength martensite aged steel contains the following ingredients in percentage by weight: 17-19% of Ni, 8-10% of Co, 4.5-6.5% of Mo, not higher than 0.08% of C and the balance of Fe and unavoidable impurities. The preparation method of the metal powder injection molded high-strength martensite aged steel comprises the following steps: adding a binder to the above powder materials according to a certain proportion to form a combination, mixing and milling the combination, crushing, injection molding, degreasing, sintering, carrying out solution treatment and ageing. By replacing a smelting production process with a metal injection molding process, three-dimensional irregular metal powder injection molded high-strength martensite aged steel structural parts can be manufactured through one-time molding; by adopting second-time solid-solution process treatment and ageing treatment, the metal powder injection molded high-strength martensite aged steel has the advantages that the tensile strength is over 1,500MPa, the elongation percentage is 10%, the impact strength is over 50J / cm<2>, and the hardness is HRC40-48.

A method of forming an earth-boring tool includes introducing metal into a die, rotating the die to generate centrifugal forces on the metal, and cooling the metal in the rotating die. A rotary drill bit may include a unitary, centrifugally cast bit body including an integral shank, at least one blade, and at least one cutting element on the blade. A rotary drill bit or a roller cone may include a first centrifugally cast material and a second centrifugally cast material. Another rotary drill bit includes a bit body comprising a maraging steel alloy. A method of forming a rotary drill bit may include disposing cutting elements on a rotary drill bit comprising maraging steel and aging the rotary drill bit to form at least one intermetallic precipitate phase. Methods of repairing a rotary drill bit include annealing and aging at least a portion of a rotary drill bit.

The invention provides ultra-strength and high toughness maraging steel and manufacturing method thereof. The maraging steel comprises the following chemical components: less than or equal to 0.03 weight percent of C, less than or equal to 0.10 weight percent of Mn, less than or equal to 0.10 weight percent of Si, less than or equal to 0.05 weight percent of S, less than 0.010 weight percent of P,17.50 to 20.50 weight percent of Ni, 2.00 to 4.00 weight percent of Mo, 1.00 to 1.75 weight percent of Ti, 0.05 to 0.15 weight percent of Al, 0.0005 to 0.002 weight percent of B, 0.005 to 0.10 weightpercent of Zr+Ca, and the balance of Fe and inevitable impurities. By adopting Ni-Mo-Ti-Al alloying, the maraging steel meets the requirements of good comprehensive properties such as high strength and toughness, which is suitable for high-end products such as thin-wall parts, high-grade moulds and springs.

The invention discloses an ultra-low-carbon (ULC) high-purity industrial pure iron and a production method thereof. The invention is mainly characterized in that: the ULC high-purity industrial pure iron contains chemical elements in weight percentage as follows: C is less than or equal to 0.008 percent, Si is less than or equal to 0.05 percent, Mn is less than or equal to 0.05 percent, S is less than or equal to 0.002 percent, P is less than or equal to 0.005 percent, and Al is less than or equal to 0.055 percent. The materials with the proportions of the above chemical compositions are smelted for dephosphorization and desulfurization in an arc furnace, blown with oxygen for decarbonization by AOD (argon-oxygen decarburization), and desulfurized under high temperature and high alkalinity, and finally cast into steel ingots; therefore, the purity of the steel ingots produced by the method can reach 99.5 to 99.7 percent. The maraging steel trial produced by the pure iron of the invention can reach the best level of the steels in China; the pure iron produced by the method of the invention can also improve the performance of other steels such as 00Ni12Cr5Mo3AlTiVA, and push the research and development of high-purity steels.

A maraging steel preferably without cobalt, having the following chemical composition: Ni 18-23 wt. %, Mo 4.5-8 wt. %, Ti 1-2 wt. %, Al 0-0.3 wt. %, C< / =0.01 wt. %, remainder Fe and impurities. The composition also preferably satisfies the following conditions: Ni+Mo=23-27 wt. %, inclusively; Ni+3xMo+20xTi+10xAl> / =60 wt. %.

A golf club head includes a front member, a rear member and a neck connected together to form a housing. The front member, which is made of a flexible material, such as aluminum alloy, stainless or Maraging steel, has a face and an annular wall projected from a back of the face to form a cup-like member, wherein the wall has a connecting portion at a distal end thereof, and a length of the wall is identical to or greater than 8 mm and a thickness of the wall is identical to or less than 2 mm. The rear member, which is made of a light metal, such as magnesium alloy or aluminum alloy, has a connecting portion to engage the connecting portion of the front member. The neck is fixed on the rear member.

The method discloses a forging forming method of a low-pressure turbine shaft made of C250 maraging steel, which is provided for obtaining a forging with a better structure and a better property. The method comprises processing steps as follows: a C250 maraging steel bar material which is subjected to blanking according to specification is heated to a forging temperature ranging from 990 DEG C to 1,040 DEG C, heated to the forming temperature again after upset and stretched, and prepared into a pre-forged blank in a forging die; the pre-forged blank is forged into a low-pressure turbine shaft forging at a strain rate of 0.015s<-1>-0.0015s<-1> in the forging die after heated to a forging temperature ranging from 1,020 DEG C to 1,060 DEG C; and the low-pressure turbine shaft forging is subjected to solid solution and aging heat treatment after forged, the solid solution is that the low-pressure turbine shaft forging is heated to 825 DEG C and is subjected to air cooling after heat insulation, and the aging is that the low-pressure turbine shaft forging is heated to 485 DEG C and is subjected to air cooling after heat insulation. The forging is mainly used for being prepared into a low-pressure turbine shaft part of an aero-engine.

A precipitation-hardened stainless maraging steel which exhibits a combination of strength, toughness, and corrosion resistance comprises by weight about: 8 to 15% chromium (Cr), 2 to 15% cobalt (Co), 7 to 14% nickel (Ni), and up to about 0.7% aluminum (Al), less than about 0.4% copper (Cu), 0.5% to 2.5% molybdenum (Mo), 0.4 to 0.75% titanium (Ti), up to about 0.5% tungsten (W), and up to about 120 wppm carbon (C), the balance essentially iron (Fe) and incidental elements and impurities, characterized in that the alloy has a predominantly lath martensite microstructure essentially without topologically close packed intermetallic phases and strengthened primarily by a dispersion of intermetallic particles primarily of the eta-Ni3Ti phase and wherein the titanium and carbon (Ti) and (C) levels are controlled such that C can be dissolved during a homogenization step and subsequently precipitated during forging to provide a grain-pinning dispersion.

The invention discloses a gas nitriding process of 00Ni18Co8Mo5AlTi high-strength maraging steel, which comprises the procedures of: carrying out the solution treatment on raw materials and processing parts into the finished size; laying ammonium chloride and quartz sand through drying and uniformly blending at the bottom of a nitriding tank; eliminating grease dirt and drying 00Ni18Co8Mo5AlTi steel parts; carrying out the sand blasting processing on the parts before the nitriding processing; introducing ammonia and discharging air in the tank after enchasing and sealing the parts, carrying out the nitriding processing by a two-stage method during temperature rise along with a furnace when the resolution ratio of the ammonia in the tank is zero; switching off a power supply of a heating furnace and continuously supplying the gas to maintain the positive pressure in the nitriding tank when the nitriding processing and temperature maintenance are finished; removing the nitriding tank from the heating furnace and cooling in the air when the temperature is reduced to be below 300 DEG C along with the furnace; and stopping supplying the gas and taking out the nitriding parts when the temperature of the nitriding tank is reduced to be below 150 DEG C. The invention can ensure that the distortion of the size and the shape of the nitriding parts is less; the heart has good strength, plasticity and toughness; and the abrasive resistance and the fatigue resistance on the surface of the nitriding parts can be remarkably enhanced.

A golf head of present invention comprising: A top part makes from light materials with the specific gravity is under 3. The top part provides a neck portion with an axis hole therein for a golf club to plug in. A bottom part mounts under the top part and makes from metals with the specific gravity is over 4. A face part with cup shape has a face and the edge of the face extrudes backward to from a plate potion, the face part mounts in front of the bottom part and the top part and makes from elastic metals like titanium alloy, stainless steel or maraging steel.

The invention discloses a method for preparing martensite aging steel based on injection molding. The martensite aging steel comprises Fe and the following components in percentage by mass: 17.5-18.5%of Ni, 8.5-9.5% of Co, 4.5-5.5% of Mo; and the method comprises the following steps: (1) Ni, Co, Mo and Fe atomizing alloy powder is prepared; (2) other components in the martensite aging steel are added in a form of carbonyl powder; and atomizing alloy powder in the step (1) and the carbonyl powder are mixed according to a mass ratio of (0.5-2): 1 to obtain a premixture; (3) the premixture and abinding agent are mixed for banburying, and is injected for molding by an injection molding machine; (4) nitric acid is used for catalytic degreasing; (5) the sintering is performed; and (6) the heattreatment is performed. In catalytic degreasing, the corrosion of Co by nitric acid can be prevented, so that the comprehensive performance of the martensite aging steel is excellent, the yield strength and the tensile strength are high, and the hardness is higher.

A precipitation-hardened stainless maraging steel which exhibits a combination of strength, toughness, and corrosion resistance comprises by weight about: 8 to 15% chromium (Cr), 2 to 15% cobalt (Co), 7 to 14% nickel (Ni), and up to about 0.7% aluminum (Al), less than about 0.4% copper (Cu), 0.5 to 2.6% molybdenum (Mo), 0.4 to less than about 0.75% titanium (Ti), up to about 0.5% tungsten (W), and up to about 120 wppm carbon (C), the balance essentially iron (Fe) and incidental elements and impurities, characterized in that the alloy has predominantly lath martensite microstructure essentially without topologically close packed intermetallic phases and strengthened primarily by a dispersion of intermetallic particles primarily of the eta-Ni3Ti phase and wherein the titanium and carbon (Ti) and (C) levels are controlled such that C can be dissolved during a homogenization step and subsequently precipitated during forging to provide a grain-pinnning dispersion.

The object of the present invention is to manufacture mechanically manipulated rotary tools, preferably drilling, milling, grinding and cutting tools, which have stable corrosion resistance and biocompatibility, but also have high mechanical strength properties and good ductility . For this purpose, the present invention relates to the use of a precipitation-hardening martensitic stainless chromium-nickel steel having the following composition (in wt.-%): chromium: 10 to 14, nickel: 7 to 11, molybdenum: 0.5 to 6, copper: 0.5 to 4, aluminum: 0.05 to 0.55, titanium: 0.4 to 1.4, carbon + nitrogen: up to 0.3, sulfur: less than 0.05, phosphorus: less than 0.05, manganese: up to 0.5, silicon: up to 0.5, tantalum, niobium, vanadium and tungsten: maximum content of 0.2 each, cobalt: up to 9.0 when appropriate, boron: 0.0001 to 0.1 when appropriate, the remainder being iron and usual impurities.

The method discloses a forging forming method of a fan shaft made of C250 maraging steel, which is provided for obtaining a forging with a better structure and a better property. The method comprises processing steps as follows: a C250 maraging steel bar material which is subjected to blanking according to specification is heated to a forging temperature ranging from 1,000 DEG C to 1,060 DEG C, heated to the forming temperature again after upset and stretched, and prepared into a pre-forged blank in a forging die; the pre-forged blank is forged into a fan shaft forging at a strain rate of 0.01s<-1>-0.001s<-1> in the forging die after heated to a forging temperature ranging from 1,000 DEG C to 1,020 DEG C; and the fan shaft forging is subjected to solid solution and aging heat treatment after forged, the solid solution is that the fan shaft forging is heated to 820 DEG C and is subjected to air cooling after heat insulation, and the aging is that the fan shaft forging is heated to 480 DEG C and is subjected to air cooling after heat insulation. The forging is mainly used for being prepared into a fan shaft part of an aero-engine.

A metal ring made of maraging steel is heated in the presence of a halogen compound gas, so as to eliminate an oxide film from the surface of the metal ring and to form a halogenous compound film. Thereafter, the metal ring is heated under a vacuum or reduced pressure atmosphere to eliminate the halogenous compound film, and then it is maintained under an atmosphere comprising ammonia at a processing temperature ranging between 450° C. and 500° C. for a processing time ranging between 30 and 120 minutes, so as to carry out a nitriding processing. The above nitriding processing comprises the steps of: placing the above metal ring into a heating furnace and raising the temperature inside the heating furnace to the above processing temperature; introducing a first mixed gas consisting of 50% to 90% ammonia byvolume, 0.1% to 0.9% oxygen by volume, and a residual volume consisting of nitrogen into the heating furnace, and maintaining the above processing temperature, so as to form a nitrided layer on the surface of the metal ring; and when the one-third to one-half of the processing time has passed, replacing the atmosphere inside the heating furnace by a second mixed gas consisting of 0% to 25% ammonia by volume and a residual volume consisting of nitrogen, and maintaining the above processing temperature until the remaining processing time passes.

The invention discloses a forging method for a maraging steel disc-shaft integrated forged piece. According to the technical scheme for achieving formation of the disc-shaft integrated forged piece through one heating number, avoiding local idle burning of the forged piece and lowering the production difficulty of the forged piece, the traditional final forging temperature of the maraging steel forged piece is adjusted to 750 DEG C from 820-870 DEG C, the traditional technique that disc upsetting is conducted after rod pulling is changed into the technique that rod pulling is conducted after disc upsetting, then effective protective measures are taken in the deformation process of the forged piece, and the effect that formation of the forged piece is completed through one heating number on the premise that the requirement for the final forging temperature is met is guaranteed. According to the technical scheme, the operability is high, the forging method is suitable for popularization, and the preparation technique for the disc-shaft integrated forged piece and particularly for a large disc-shaft integrated forged piece with the length exceeding 2000 mm is remarkably improved.

A steel for machine structural use with a better strength-ductility-toughness balance than maraging steel and applications thereof are provided. The steel for machine structural use with excellent strength, ductility, and toughness contains, in percent by mass, more than 0.30% to 0.5% of carbon, 1.0% or less of silicon, 1.5% or less of manganese, 0.025% or less of aluminum, 0.3% to 0.5% of molybdenum, and 0.0005% to 0.01% of boron, and the balance is iron and incidental impurities. The steel has a structure including at least 90% by volume of martensitic structure. The martensitic structure includes blocks having a size of 1.5 μm or less. Dissolved boron is contained in an amount of at least 0.0005% and is present at boundaries of prior austenite grains in a concentration at least 1.5 times that in the prior austenite grains.

A metal ring made of maraging steel is heated in the presence of a halogen compound gas, so as to eliminate an oxide film from the surface of the metal ring and to form a halogenous compound film. Thereafter, the metal ring is heated under a vacuum or reduced pressure atmosphere to eliminate the halogenous compound film, and then it is maintained under an atmosphere comprising ammonia at a processing temperature ranging between 450 DEG C and 500 DEG C for a processing time ranging between 30 and 120 minutes, so as to carry out a nitriding processing. The above nitriding processing comprises the steps of: placing the above metal ring into a heating furnace and raising the temperature inside the heating furnace to the above processing temperature; introducing a first mixed gas consisting of 50% to 90% ammonia by volume, 0.1% to 0.9% oxygen by volume, and a residual volume consisting of nitrogen into the heating furnace, and maintaining the above processing temperature, so as to form a nitrided layer on the surface of the metal ring; and when the one-third to one-half of the processing time has passed, replacing the atmosphere inside the heating furnace by a second mixed gas consisting of 0% to 25% ammonia by volume and a residual volume consisting of nitrogen, and maintaining the above processing temperature until the remaining processing time passes.

A machining technology for the aged 18(Ni)-series non-Co martensite steel with high strength and toughness includes hot working, cold working by direct cold rolling or machining without solution treatment, ageing at 400-600 deg.C for 0.5-3 hrs, and air or water cooling. Its advantages are short period and simplified heat treatment.

Maraging steel with improved machinability, good weldability, and high corrosion resistance, a process for the heat treatment of such a steel, as well as its use. According to the invention this steel contains (in % by weight) 0.02-0.075% carbon; 0.1-0.6% silicon; 0.5-0.9% manganese; 0.08-0.25% sulfur; maximum 0.04%; phosphorus; 12.4-15.2% chromium; 0.05-1.0% molybdenum; 0.2-1.8% nickel; maximum 0.15% vanadium; 0.1-0.45% copper; maximum 0.03% aluminum; 0.02-0.08% nitrogen; as well as optionally one or more additional alloying elements up to maximum 2.0%, residual iron, and impurities caused in manufacturing, and a ferrite percentage in the structure of less than 28% by volume. A process is also provided for the heat treatment of a maraging steel with improved machinability, which process makes an object that is through-hardened even with a large cross-section, lies essentially in that a steel block with the above composition is subjected in a first step to an annealing treatment for the formation and adjustment of a ferrite percentage in the structure and in a second step a hot forming of the same takes place, after which in a third step a soft annealing and then a thermal tempering are performed.

Provided is a maraging steel strip which has such a composition that can reduce the content of TiN acting as the starting point of fatigue fracture in a high-cycle region, and the bending fatigue strength of which has been improved by the precipitation hardening effect yielded by precipitating coherent nitrides in the nitrided structure. A maraging steel strip produced by nitriding a managing steel which contains by mass, C: 0.01% or less, Si: 0.1% or less, Mn: 0.1% or less, P: 0.01% or less, S: 0.005% or less, Ni: 8.0 to 22.0%, Cr: 0.1 to 8.0%, Mo: 2.0 to 10.0%, Co: 2.0 to 20.0%, Ti: 0.1% or less, Al: 2.5% or less, N: 0.03% or less, and O: 0.005% or less, with the balance being Fe and unavoidable impurities, wherein Baker-Nutting orientation relationship with an orientation difference within 10° exists between the Cr nitride precipitated in the nitrided layer and the matrix martensite.

The invention provides maraging steel used for a metal belt. The maraging steel can reduce the composition forming the starting point TiN of a fatigue failure in a high-cycle region, and nitrogen treatment is easy to perform to improve surface hardness; moreover, the compressive residual stress of a surface nitride layer is increased to improve the bending fatigue strength; in addition, the maraging steel is also used for the micronization of old austenitic grain which ensures high strength and ductility. The maraging steel is characterized by comprising the following components in percent by mass: less than 0.01 percent of C, less than 0.1 percent of Si, less than 0.1 percent of Mn, less than 0.01 percent of P, less than 0.005 percent of S, 17.0 to 22.0 percent of Ni, 0.1 to 4.0 percent of Cr, 3.0 to 7.0 percent of Mo, greater than 7.0 percent and less than 20.0 percent of Co, less than 0.1 percent of Ti, less than 2.5 percent of Al, less than 0.03 percent of N, less than 0.005 percent of O, less than 0.01 percent (excluding 0 percent) of B, 8.0 to 15.0 percent of Co / 3+Mo+4Al, and the balance Fe and unavoidable impurities.

The invention discloses a forming method of a solid rocket engine shell, and belongs to the technical field of medium-sized solid rocket engines. The forming method comprises the steps that an engineshell is divided into a front joint, a rear joint, a front skirt body, a rear skirt body, a front slide block, a rear slide block, a front butterfly body, a rear butterfly body, a first cylinder bodypart and a second cylinder body part, then each part is welded and formed at the corresponding positions to make the engine shell, and wherein each part is made of C250 maraging steel. According to the forming method, the engine shell is made of the C250 maraging steel, the high-temperature heat treatment is avoided during specific preparation, and the shell shape and position tolerance accuracy is higher; and at the same time, the specific process comprises the processes of ellipsoid drawing forming, high-resistance maraging steel cylinder spinning forming and the like, the problem of drawingforming difficulty of the material is solved, and meanwhile the technical defect of low material utilization rate caused by adopting a traditional integral forging processing scheme is further avoided.

The invention discloses a method for preparing a high-performance maraging-steel steel belt. The method comprises the following steps of vacuum smelting, vacuum self-consuming, homogenizing, forging, hot-rolling, cold-rolling and ageing, wherein the vacuum smelting step is used for batching maraging-steel according to components and percentage content, and placing batched materials in a vacuum induction furnace according to a set sequence; the vacuum self-consuming step is used for using smelted steel ingot as a self-consuming electrode, placing the self-consuming electrode in a vacuum self-consuming electric-arc furnace and carrying out vacuum self-consuming crystallization and re-smelting; the ageing step is used for placing the cold-rolled steel belt into a liquid nitrogen slot at -196 DEG C, preserving heat for 2 hours at a ultralow temperature, then taking out the steel belt, placing the steel belt in a vacuum thermal treatment furnace after naturally cooling the steel belt to the room temperature, and taking out after preserving heat for 2-4 hours at 450-500 DEG C to obtain high-performance maraging-steel steel belt. The method disclosed by the invention further improves mechanical strength of the steel belt, further improves toughness of the steel belt at the same time, and satisfies industrial needs better.

A golf club head includes a front member, a rear member and a neck connected together to form a housing. The front member, which is made of a flexible material, such as aluminum alloy, stainless or Maraging steel, has a face and an annular wall projected from a back of the face to form a cup-like member, wherein the wall has a connecting portion at a distal end thereof, and a length of the wall is identical to or greater than 8 mm and a thickness of the wall is identical to or less than 2 mm. The rear member, which is made of a light metal, such as magnesium alloy or aluminum alloy, has a connecting portion to engage the connecting portion of the front member. The neck is fixed on the rear member.