28622599
28622598
Fax:0755-28620232
81836123
Address: Longgang District, Shenzhen street Au Au Pui Second Industrial Zone Property Management Third District No. 33 Industrial Park on the third floor, a far
The screw production process (a) - annealing
Objective: A, the wire is heated to a proper temperature, keep a certain time, and then slowly cooling, in order to adjust the crystal structure, reduce the hardness, improved processing of wire at room temperature.
Two, work flow:
(a), feeding: will need to product dipping furnace processing, pay attention to the furnace cover should be tightly. Generally a furnace can be processed at the same time 7 volumes (about 1.2 tonnes / volume).
(two): will the temperature inside the furnace, heating slowly (about 3-4 hours) to the specified temperature.
(three): 1018, 1022, heat preservation material wire to keep 4-6h at 680 DEG -715 DEG C, the material is 10B211039, CH38F wire at 740 DEG -760 DEG to keep 5.5-7.5 H.
(four): will the furnace temperature, cooling slowly (about 3-4 hours) to 550 DEG C, and then with the furnace cooling to room temperature.
Three, quality control:
1, hardness: material for 1018, 1022 wire after annealing hardness is HV120-170, the material is carbon wire after annealing hardness is HV120-180.
2, appearance: the surface must not have the oxidation and decarburization.
The screw production process (two) - pickling
A, objective: to remove the oxide film on the surface of the wire, and a layer of phosphate film is formed on the metal surface, so as to reduce the wire rod pumping line and cold pier or forming processing process, abrasion of tool and die.
Two, work flow:
(a), pickling: will the entire disk element were immersed in normal temperature, concentration of three hydrochloric acid tank 20-25% minutes, the purpose is to remove the oxide film on the surface of wire rod.
(two), water: remove hydrochloric acid corrosion product of wire rod surface.
(three), oxalic acid: increased metal activity, in order to make the film the next process generates more compact.
(four), film processing: the plate element immersed in phosphate, iron and steel surface and chemical treatment of liquid steel contact, dissolve insoluble compounds (such as Zn2Fe (Po4) 2 - 4H2o), attached to the formation of a coating on the surface of iron and steel.
(five), water: clear coating surface residue.
(six), phosphate coating lubricant: because the friction coefficient is not very low, lubrication can not give processing fully, but with metal soap (such as sodium soap) react to form metal soap layer of hard, can increase the lubrication performance.
The screw production process (three) -- pumping line
First, objective: the disc element cold drawn to a desired line diameter. The utility for some products can be divided into roughing (peeling) and sperm extraction in two stages.
Two, work flow
Plate element by pickling, through the pumping line machine cold drawn to a desired line diameter. Suitable for large screws, nuts, threaded rods for wire rod.
The screw production process (four) -- forming
One purpose: the wire after cold forging (or hot forging), in order to achieve the shape of semi finished and length (or thickness).
Two, work flow:
1, six angle bolt (four die four red or three die three blow)
(1), cut through the movable scissors: one-way move will card in shear modulus in wire cut to the desired blank.
(2), a punch: after counter die extrusion die blank blank, preliminary molding die, after the blank is introduced.
(3), two Chong: embryo feed into the second die, two die extrusion, blank was oblate shape, after the blank is rolled out die.
(4), three Chong: embryo feed into the third die, die shear angle by six three kernel, after embryo feed six hexagon head, after preliminary formation, mold the embryo material into the third die, cutting off from six angle of the head, six head formation.
2, six angle bolt (three die three blow)
3, screw (general type one die two blow)
(1), cut through the movable scissors: one-way move will card in shear modulus in wire cut to the desired blank.
(2), a punch: die is fixed, a die head will be preliminary molding products, to enable the next stroke can completely formed. When the product is a cutting groove, a die is a concave, elliptical groove, products for the cross groove, a concave die for square groove.
(3), two Chong Chong Chong out: after the overall operation, two die move to die in front of two die, at the same time moving forward will be the final product molding. After the blank is introduced by backlash bar.
Three, hot
1: in the heating equipment, heating the blank shaped end heated to white hot state, setting heating temperature and time on the basis of product specifications. The following general 3/4 heating 7-10 seconds, 7/8-1 "heating about 15 seconds.
2, forming: the heated blank quickly moved to the molding machine, by the back seat, clamping die fixed die head impact blank, to forming. Can be adjusted according to the length of the blank distance back.
3, beam to beam rod: rod machine by extrusion product rod.
Thermal also play red.
Four, nut shaping:
(a), operation process:
1, cut off: it is composed of an inner knife mold (410) and (301) with the shear cutter, wire cut to the desired blank.
2, a punch: by the former die (111), stroke die (411), rod (211) with backlash, rough cut blank deformation to plastic, and by the backlash rod (211) the blank is introduced.
3, two rushed: running clip (611) the embryo material from a punch clamp to two Chong, composed of a front die (112), stroke die (412), (412) after stick cooperation, further the blank shaping, and strengthen the applanation first rushed and full angle effect, followed by the back bar (212) the blank is introduced.
4, three rushed: running clip (612) the embryo material from two to three punching punching clamp, composed of a front die (113), stroke die (413), rod (213) with back again extrusion blank, in order to make the undershoot can fully formed, followed by a back rod (213) the blank is introduced.
5, four: operation of punching clamp (613) the embryo material from three to four punching punching clamp, composed of a front die (114), stroke die (414), rod (214) with the backlash, the screw cap is fully formed, and by controlling iron thickness adjusting nut thickness, followed by a back rod (214) the blank is introduced.
6, five: operation of punching clamp (614) the embryo material from four to five punching punching clamp, composed of a front die (119), de tray (507) coordination, the blank punching completely molding, and the thrust of the iron into punch mould kernel, and finally complete nut forming. In this process the formation of head marking nut.
The screw production process (five) -- Rolling
Objective: A, has been formed semi finished rolling or tapping screw to achieve the desired. The utility for bolt (Luo Si) called the rolling teeth, tooth bar called rolling, called tapping nut.
Two, rolling: threading is a dental plate is fixed, another piece of movable tooth plate drives the mobile products, extrusion products produced by plastic deformation, the formation of the desired thread.
Three, tapping: tapping is nut has molding, using taps, the formation of the desired thread.
Four, rolling: rolling with two corresponding to the screw roller, the positive rotation, the use of extrusion products to produce plastic deformation, the formation of the desired thread. Rolling is usually used for teeth.
The screw production process (six) - heat treatment
First, heat treatment: according to different objects and purposes can choose different heat treatment method.
Quenched and tempered steel after quenching and high temperature tempering: (500-650 DEG C)
Spring steel, medium temperature tempering after quenching (420-520 C)
Carburizing steel: carburizing and quenching and low temperature tempering (150-250 C)
Low carbon and medium carbon steel (alloy) into martensite after quenching, with the increase of tempering temperature, the general rule is the decrease of strength, and the plasticity and toughness rise. But because of low and medium carbon steel carbon content in the different effect of tempering temperature on the degree of different. So in order to obtain good comprehensive mechanical properties, may take the following approach respectively:
(1), the selection of low carbon steel (alloy), after quenching and low temperature tempering 250 DEG C, in order to obtain low carbon martensite. In order to improve the surface wear resistance of this kind of steel, only by improving the carbon content of the surface, i.e. surface carburizing, commonly known as carburizing steel structure.
(2), take in carbon steel containing higher carbon, quenching after high temperature (500-650 DEG C) tempering (the so-called modified treatment), so that it can in high plastic case, maintaining sufficient strength, generally called this kind of steel is quenched and tempered steel. If you want to get high strength, rather than reduce the plasticity and toughness of carbon containing gold content, Quenched and tempered low can adopt low temperature tempering, is the so-called "ultra high strength steel".
(3), steel carbon content ranged between carbon and high carbon (such as 60, 70 steel) and some high carbon steel (such as 80, 90 steel), if used in the manufacture of spring, in order to guarantee the high elastic limit, yield limit and fatigue limit, using medium temperature tempering after quenching.
(4), decarburization: refers to the black metal material (steel) surface loss of carbon. There will be a decarburization heat treatment, minor decarburization is allowed, depth of decarburized layer surface hardness. Decarburization layer is deeper, the smaller the surface hardness value.
The specific detection based on GB3098.1
Two, work flow:
Annealing (pearlitic steel)
1, preheat treatment: normalizing
High temperature tempering (martensitic steel)
(1), normalizing the purpose is grain refinement, reducing banding in the organization, and adjust the hardness, easy machining, normalizing, with equiaxed fine grain steel.
2, quenching: steel body is heated to 850 DEG C for quenching, quenching medium according to the size of steel parts and the hardenability of the steel to be selected, the general choice of water or oil or air quenching. In the quenched steel, low plasticity, large internal stress.
3, the tempering:
(1), in order to make the steel has high plasticity, toughness and proper strength, steel high temperature tempering at 400-500 DEG C, to temper brittleness sensitivity of large steel, tempering must quickly cooling, suppress the occurrence of temper embrittlement.
(2), if the requirements of parts with special high strength, is tempered at 200 degrees Celsius, get the medium carbon tempered martensite.
(two), spring steel:
1, the quenching oil quenching to 830-870 DEG C.
2, the tempering: tempering to 420-520 DEG C, obtaining troostite tissue.
(three), carburizing steel:
1, carburizing: a chemical heat treatment, that under certain temperature in the active medium containing a chemical element, element to the steel surface infiltration C. Divided into preheating (850 DEG C) carburizing (890 DEG C) diffusion (840 DEG C) process
2, quenching: carbon and low alloy carburizing steel, generally using a direct quenching or quenching.
3, the tempering: low temperature tempering to eliminate internal stress, and improve the strength and toughness of the carburized layer.
The screw production process (seven) - surface treatment
A, surface treatment of type:
Surface treatment is a process of cover layer formed on the surface of the workpiece through a certain method, its purpose is assigned to product surface appearance and corrosion effect, surface treatment methods are attributed to the following methods:
1, plating: plating parts will accept immersed in aqueous solution by the deposition of metal containing compounds, to the current through the bath, make the metal plating and precipitates on the part. Common electroplating galvanized, copper, nickel, chromium, copper nickel alloy, sometimes to cook black (blueing phosphating etc.), including.
2, hot dip galvanizing: through the immersion temperature carbon steel parts is about to complete melting zinc plating bath at a temperature of 510 DEG C within the. The result is a Fe Zn alloy on the surface of steel parts gradually into the passivation of zinc products on the outer surface of the. Hot dip aluminizing is a similar process.
3, mechanical plating: coating metal by particles to impact the surface of the product, and the surface coating to the cold welding products.
Two, quality control:
Electroplating quality to its corrosion resistance ability as the main measure, followed by the appearance of. Corrosion resistance is imitation products work environment, set to test conditions, to corrosion tests of its. The quality of the electroplating product to be controlled from the following aspects:
1, appearance:
The surface of the product does not allow local without coating, burning, rough, dull, peeling, crust status and obvious stripe, a pinhole pitting, black plated slag, the passivation film loose, cracking, shedding and serious passivation traces are not allowed.
2, the thickness of coating:
Working life in corrosive atmosphere in the fastener and the coating thickness is proportional to its. Economic plating thickness is generally recommended for 0.00015in ~ 0.0005 in (4 ~ 12um).
Hot dip galvanizing: the average thickness of the standard is 54 um (called size smaller than 3/8 is 43 UM), the minimum thickness of 43 um (called size smaller than 3/8 is 37 um).
3, coating distribution:
Using different deposition methods, coating in fasteners on the surface aggregation in different ways. Electroplating coating metal is not uniformly deposited on the peripheral edge, corner to obtain thick coating. In the threaded part of fasteners, the thickness of the coating is arranged along the crest of the thread, the thread side thin gradually, in the tooth bottom deposited at the thinnest, and hot dip galvanizing is just the opposite, deposition of thick, angle and the bottom of the thread, metal deposition coating tendency and thermal mechanical plating plating the same, but the more smooth and far more uniform on the whole surface thickness.
4, hydrogen embrittlement:
Fasteners in the processing and processing, especially electroplating process in acid cleaning and alkali wash before plating and subsequent, surface absorption of hydrogen atoms, the metal deposition and hydrogen trapping. When the fastener is tightened, hydrogen toward the most stress concentrated part turn enough, causing the pressure increased to more than the base metal strength and rupture of minimal surface. Hydrogen special activities and soon to the newly formed crack to. This pressure - rupture - infiltrate the cycle continues to the fastener fracture. Usually occurs in the first should be within a few hours after force application.
In order to eliminate the threat of hydrogen embrittlement, fasteners in plating as soon as possible after heating baking, so that hydrogen permeation from the coating, baking is usually in the 375-4000F (176-190 DEG C for 3-24 hours).
Due to mechanical galvanizing is non electrolyte, which virtually eliminated the threat of hydrogen embrittlement. The other as the engineering standards prohibit the hardness is higher than that of HRC35 fasteners (Gr8 imperial and metric of level 10.9 or above) hot dip galvanizing. So the fasteners of hot dip little hydrogen embrittlement.
5, adhesion:
With a solid point and considerable pressure to cut or pry. If on the tip of the front, coating in sheet or skin peeling off, so that the exposed base metal shall be deemed insufficient, adhesion.
Screw surface defects
Analysis of the adverse phenomenon is easy to produce a, heading and reason
1, two eccentric: Chong poor installation and adjusting machine improper.
2, Waitoushan: a poor installation and adjusting machine improper blanking.
3, the head does not circle: the improper choice of a die or a punching molding is not full.
4, die crack: Die rupture or play mode R angle properly, to make the mold is two impact scraping.
5, double: a bad head punching molding.
6, flash: a punching molding bad, mainly between punch and die hole clearance is too large or too short cause thrust rod.
7, crack angle: the punching needle punching and die cracking or two phase weight.
8, head cracking: material problems, or a die using the wrong (a die if hit pan head with six angle washer head), and the reason of lubricating oil.
Analysis of adverse phenomena and causes of two common, rolling
1, processing crack: old and regulating improper tooth board machine.
2, blunt tail: adjusting the machine properly, tooth plate is too old.
3, fire: two tooth plate spacing is too large, or the feeding time is wrong.
4, cocked tail: tooth plate control seat screw too far.
5, tail: tooth wear plate and adjusting machine improper.
6, asan not satisfied: improper adjustment machine
7, dinner is not to rub the tip of the tail.
8, crooked rod: correction block is not nice. 9, the tooth bottom roughness: pitch is not set.