CN1183326A - Method for making composite screw - Google Patents

Abstract

A method for manufacturing screw with different materials includes manufacturing screw head and rod with different materials, friction joinning of screw head with rod, threading on the rod, heat treatment and electroplating, and features simplified process, and better torsion strength and anticorrososion nature of obtained screw.

Description

The manufacture method of composite screw

The present invention relates to a kind of screw manufacture method, particularly relate to a kind of manufacture method of composite screw.

The general screw that adopts, to make with carbon steel or stainless steel, its advantage and shortcoming are respectively arranged in the use, the screw that forms with the carbon steel material forging, although expense cost is lower,, the antirust ability of this kind screw is poor, affected by aqueous vapor or environmental change, and destroy rapidly screw structural and reduce screw the sealed power when using. Other has the better stainless steel screw of a kind of corrosion protection ability, although improved the corrosion protection ability of screw, but, large because of the work hardening of this screw, formability is poor, expense cost is high and be difficult to nitrogen treatment reaches from boring requirement, still has in the use following problem:

Although the screw of a stainless steel can utilize nitrogen treatment to improve the hardness on screw surface, but, because boring tail, the screw of stainless steel is difficult to forging and molding, and still lack at present and satisfy screw from the nitrogen treatment technology of boring function, so that the hardening effect of screw is not good, and after the screw via nitride processing because of stainless steel, make easily stainless steel produce the problem of crystal boundary corrosion, and destroy original anti-corrosion performance.

Two, for this CARBURIZING FURNACE FOR STAINLESS FASTENER is had from attacking and certainly bore function, as shown in Figure 1, be welded to each other with the body of rod 12 of stainless head 11 with high-carbon steel, recycle at last Quenching Treatment and form, still, when welding, this high-carbon steel welding heat affected zone hardness is too high, make easily joint 13 produce the crack, cause the screw thread 14 formability variation of this screw 1, and affect the threaded mold life-span. And Quenching Treatment is so that the screw thread 14 of this high-carbon steel material and brill afterbody 15, make screw thread 14 and 15 fractures of brill afterbody easily because of fully hard embrittlement in construction.

Three, in order to avoid the too high shortcomings such as producing easily the crack that reaches of high-carbon steel and stainless steel welding heat affected zone hardness, as shown in Figure 2, the body of rod 22 with mild steel is welded to each other with stainless head 21, make again at last composite screw 2 with Carburization Treatment, but, the expense cost that this composite screw 2 carries out Carburization Treatment is higher, and the carbon contamination of stainless head 21 when being subjected to Carburization Treatment easily, so that the original anti-corrosion property of stainless steel is destroyed.

As shown in Figure 3, in addition, composite screws in the past also has a kind of manufacture method, to forge first or cut into to contain shoulder 91 (shown in chain-dotted line) and without the screw thread shank or contain the round bar 92 that bores afterbody, this circle bar 92 is after carburizing and appropriate heat treatment, weld again with without the basic stainless head 93 of roll threading austenitic iron (Austenitic iron), form a proper width without the carburizing harden zone, and then the burr 94 of rear protrude out outside composite screw 9 are welded in cutting, and (97 of the screw front ends situation of looking determines whether remove with shoulder 91, with Transformatin among the figure), carry out at last screw thread 95 and roll over tooth shaping, Quenching Treatment, just can form a composite screws 9 that anti-corrosion performance is good.

Although the anti-corrosion property of the above-mentioned composite screw of making is good, but, still have following shortcoming in the manufacturing:

One, construction procedure is complicated, and expense cost is high:

Because behind the round bar that should the engage 92 necessary first forging and moldings, cut again this shoulder 91, just be welded to each other with head 93, and must again the burr 94 (as shown in Figure 3) of weld be removed with shoulder 91 after the welding, and then form and the step such as heat treatment, so, in the manufacture process, this circle bar 92 must could weld with this head 93 through procedure of processings such as forging, cuttings, and also burr 94 and shoulder 91 must be removed after the welding, step is complicated, and the processing tool device that procedure of processing is employed when implementing is many, increase and make required machine, the expense costs such as manpower operation.

Two, easily distortion of screw processing, so that torsion reduces:

Behind circle bar 92 and the head 93 welding forming screws 9, this screw 9 must be rolled over tooth again and is shaped, but when rolling over tooth owing to this screw, this circle bar 92 is positioned at head 93 joints rolles over the tooth district, when so this screw 9 is rolled over tooth, these circle bar 92 inner tissues occur except making easily this circle bar 92 be subject to the spreading effect to be changed, cause joint to produce the crack, and so that outside the fraction defective when making increases, and screw thread 95 parts that are shaped when rolling over tooth can be cut this circle bar 92 and head 93 joints, and the torsion of this screw 9 is reduced.

Main purpose of the present invention is to provide a kind of manufacture method of composite screw, can effectively simplify manufacture process, and rapid shaping goes out a good screw of the better and anti-corrosion property of torsion.

Feature of the present invention is to go out head and without the body of rod of screw thread with the mother metal of unlike material is preshaped respectively, and then engage with friction welded method, make the body of rod and head mold the screw embryo material of a composite, again the screw embryo material of composite is rolled over tooth at last, and heat-treat at this screw embryo material, the step such as plating, but just rapid shaping goes out a good composite screw of the better and anti-corrosion property of torsion.

The manufacture method of composite screw of the present invention, comprise successively material preparation step, engagement step, rolling tooth step and subsequent step, first in material preparation step, the mother metal of unlike material forged in advance or cuts respectively head and without the body of rod of screw thread, then in engagement step, the body of rod is touched in the head bottom, and adopt friction welded method to engage, make this body of rod and head mold the screw embryo material of a composite, again the screw embryo material of composite is rolled over tooth (also being exactly to roll over the tooth step) at last, heat-treat at this screw embryo material, the processing (also being exactly subsequent step) such as plating, just can simplify the manufacture process rapid shaping and go out one and have better torsion and corrosion proof composite screw.

The present invention is described in detail below in conjunction with drawings and Examples:

Fig. 1 is in the past composite screws organigram of the first.

Fig. 2 is in the past composite screws organigram of the second.

Fig. 3 is the third in the past composite screws organigram.

Fig. 4 is the flow chart of the present invention's the first better embodiment processing method.

Fig. 5 is the screw structure schematic diagram of the above-mentioned better embodiment of the present invention.

Fig. 6 is the schematic diagram of the engagement step of the above-mentioned better embodiment of the present invention.

Fig. 7 is the screw structure schematic diagram of the present invention the second better embodiment.

As shown in Figure 4, the present invention comprises material preparation step 31, engagement step 33, rolling tooth step 35 and the subsequent step 37 that carries out successively, this material preparation step 31 is the mother metals with unlike materials such as stainless steel and carbon steels, preshapedly respectively go out (as forge or cutting etc. can) head and without the body of rod of screw thread, this engagement step 33 is that the body of rod is touched in the head bottom, and engage with friction welded method, make this body of rod and head mold the screw embryo material of a composite, this rolling tooth step 35 is tapping one section screw threads on the body of rod of screw embryo material, this subsequent step 37 is that the screw embryo material of composite is done heat treatment and plating, via above-mentioned steps, just can be made into the screw of a composite.

Such as Fig. 5 and cooperate shown in Figure 4, in this material preparation step 31, utilize respectively the head screw forming machine (not shown) head 41 that is shaped, utilize the guillotine (not shown) wire rod to be cut the body of rod 42 of suitable length, then carry out engagement step 33, as shown in Figure 6, again this body of rod 42 is being engaged in the mechanism 5 with head 41 difference clampings, this joint mechanism 5 is provided with one can rotating turntable 51, and one relative to this turntable 51 and can produce the travelling carriage 52 that moves in good time, this body of rod 42 is clipped on the travelling carriage 52, and these head 41 clampings are behind turntable 51, the top line face of this body of rod 42 is corresponding with the bottom surface of head 41, move close by this travelling carriage 52 to turntable 51 again, also be exactly that this travelling carriage 52 is by moving to the solid line place shown in the chain-dotted line, this body of rod 42 is touched in head 41 bottom surfaces, recycle at last the characteristic that this turntable 51 can turn round action, make this body of rod 42 and head 41 joints produce frictional heat, and frictional heat can be used as the joint method of thermal source, so that this body of rod 42 with between head 41 engages without any need for welding rod or flux, this body of rod 42 can be subject to the frictional heat effect with head 41 joints and produce engaging, these body of rod 42 apical margins are bonded in head 41 bottom surfaces, a screw embryo material 4 is shaped, simultaneously, any welding iron filings 44 that the joint 43 of this body of rod 42 and head 41 is left over, can be packed in these head 41 bottoms, and not need in addition reprocessing to remove.

Shown in Fig. 4,5, this body of rod 42 is with after head 41 engages, just roll over tooth step 35, the body of rod 42 part tappings 44 with the screw embryo material 4 after the engagement step 33, and general tapping mode is by the roll threading mould action on the tooth roller (not shown), make and be shaped spiral thread 44 on this body of rod 42, simultaneously in these body of rod 42 spreading processes, the situation of the spiral shell tooth incision that this body of rod 42 and head 41 joints can not be shaped, so the torsion that produces is better than in the past, carry out again subsequent step 37 again, with 4 heat treatments of screw embryo material and plating, can certainly attack and the composite screw that certainly bores and make one.

As shown in the table is that screw of the present invention compares with the in the past torsion test of screw, sample respectively 100, through finding after the torsion test, the composite screw that the present invention makes under the prerequisite of simplifying manufacture process, the torque value of each all is higher than in the past screw, simultaneously average torque value (127.4kgcm) be high (differing from 17.7kgcm) than screw (109.7kgcm) in the past also, in other words, utilize composite screw that the present invention makes to strengthen 16.1% than the torsion of composite screw in the past, make composite screw of the present invention in the use more in the past the screw of unlike material be good.

Experiment title: torsion square intensity		Establishing criteria: ASME/ANSEB18.6.4 1981
					Product in the past			The exploitation product
Sample number into spectrum	Actual measurement value (kgf-cm)		Sample number into spectrum	Actual measurement value (kgf-cm)
					No.001     No.002     No.003     No.004     No.005     No.006     No.007     No.008     No.009     No.010     No.011     No.012     No.013     No.014     No.015     No.016     No.017     No.018     No.019     No.020     No.021     No.022     No.023     No.024     No.025     No.026     No.027     No.028     No.029     No.030     No.031     No.032     No.033     No.034     No.035     No.036     No.037     No.038     No.039     No.040     No.041     No.042     No.043     No.044     No.045     No.046     No.047     No.048     No.049     No.050	110         114         117         108         110         112         107         114         109         115         115         118         110         112         113         108         105         110         116         115         112         116         107         113         116         114         106         109         104         113         115         109         111         108         112         109         107         109         112         116         105         108         112         107         106         113         112         111         112         109		No.001     No.002     No.003     No.004     No.005     No.006     No.007     No.008     No.009     No.010     No.011     No.012     No.013     No.014     No.015     No.016     No.017     No.018     No.019     No.020     No.021     No.022     No.023     No.024     No.025     No.026     No.027     No.028     No.029     No.030     No.031     No.032     No.033     No.034     No.035     No.036     No.037     No.038     No.039     No.040     No.041     No.042     No.043     No.044     No.045     No.046     No.047     No.048     No.049     No.050	124          129          122          134          128          133          134          125          128          129          126          132          129          130          131          122          124          129          128          125          131          130          127          129          128          124          128          127          129          122          133          127          126          132          122          126          122          123          127          131          127          130          128          131          130          124          127          126          126          132

Sample number into spectrum	Actual measurement value (kgf-cm)	Sample number into spectrum	Actual measurement value (kgf-cm)
				No.051    No.052    No.053    No.054    No.055    No.056    No.057    No.058    No.059    No.060    No.061    No.062    No.063    No.064    No.065    No.066    No.067    No.068    No.069    No.070    No.071    No.072    No.073    No.074    No.075    No.076    No.077    No.078    No.079    No.080    No.081    No.082    No.083    No.084    No.085    No.086    No.087    No.088    No.089    No.090    No.091    No.092    No.093    No.094    No.095    No.096    No.097    No.098    No.099    No.100	108        105        114        113        103        112        106        110        107        118        112        105        106        109        105        107        104        115        109        103        112        112        109        107        114        110        108        107        110        106        108        111        104        107        104        103        110        106        103        105        117        109        109        106        109        104        108        110        111        108	No.051     No.052     No.053     No.054     No.055     No.056     No.057     No.058     No.059     No.060     No.061     No.062     No.063     No.064     No.065     No.066     No.067     No.068     No.069     No.070     No.071     No.072     No.073     No.074     No.075     No.076     No.077     No.078     No.079     No.080     No.081     No.082     No.083     No.084     No.085     No.086     No.087     No.088     No.089     No.090     No.091     No.092     No.093     Na.094     No.095     No.096     No.097     No.098     No.099     No.100	128        130        122        134        135        124        128        120        123        131        129        129        127        122        131        126        134        123        126        133        131        121        123        121        133        126        125        127        132        122        128        125        130        129        122        127        130        126        125        125        129        122        127        124        126        125        134        126        128        126
Mean value	109.7	Mean value	127.4
				The torsion square is on average strengthened percentage 16.7%
Annotate: 25 ± 1 ℃ of 1 experiment temperature. 2. laboratory apparatus: torsion wrench

As shown in Figure 7 and cooperate Fig. 4, it is (identical with above-mentioned the first embodiment action, effect that the manufacture process of the second embodiment of the present invention still comprises material preparation step 31, engagement step 33 successively, roll over tooth step 35 and subsequent step 37, so no longer describe in detail), and different from above-mentioned the first embodiment be, the head 61 of this material preparation step 31 can forge the head bottom and protrude a 6mm with interior round bar 62, so that head 61 is when mutually being frictionally engaged with the body of rod 63, the rim surface of this body of rod 63 can be bonded on the ora terminalis face of this circle bar 62, finish a screw embryo material 6, this screw embryo material 6 that is shaped is when rolling over the tooth shaping, screw thread 64 sections of rolling over tooth do not reach the joint of this body of rod 63 and circle bar 62, can make composite screw keep better torsion, and reduce the fraction defective on making.

Can learn that by above-mentioned explanation the present invention has following listed advantage and effect:

One, anti-corrosion property is good:

Because after the body of rod of the stainless head of the present invention and carbon steel is frictionally engaged, this screw does not need via nitride to process or Carburization Treatment again, so can not cause stainless steel to produce the crystal boundary etching problem, and be subjected to carbon contamination because of stainless head, and the shortcoming such as cause that anti-corrosion property is destroyed, therefore, the stainless steel head place of composite screw of the present invention still has stainless anti-corrosion performance, when screw closure of the present invention behind article, expose the head outside article, can effectively resist external environmental change.

Two, manufacture process is simplified and is made conveniently:

Because the head of composite screw of the present invention and the body of rod are to utilize to be frictionally engaged to form, so that the part that can not there be melting in the crimping position of head and the body of rod and solidifies, therefore fusion weld not welding slag be involved in, the generation of pore and shrink the problem that produces the crack when solidifying and occur, so more in the past than the method for making that adopted welding, quenching etc. to process, more simple, and because the body of rod of the present invention is to be made by carbon steel, and the formability of carbon steel is good, therefore boring tail can directly utilize the mould forging and molding, be suitable for a large amount of productions, and can not damage the screw mold life-span.

Three, expense cost is low:

Because in the manufacture process of the present invention, this circle bar does not need the processing such as special forging, cutting to process, and after the body of rod and the engagement, also needn't be as remove separately shoulder or burr in the past, so, on the implementation, therefore the processing machine of employing can reduce expense costs such as making required machine, manpower operation than lacked in the past.

Four, screw processing is difficult for distortion, and torsion is good:

As above shown in the table, the composite screw that the present invention makes is relatively found with the screw that unlike material in the past consists of, screw is high in the past simplifying the composite screw torsion ratio of making in the manufacture process situation in the present invention, so in the use, the screw made of the present invention is better than the screw of unlike material in the past.

In addition, behind this body of rod and the head welding forming screw, this circle bar and engagement place can be hidden in the head bottom surface, so when rolling over the tooth forming step on this body of rod, the screw thread incision situation that this body of rod and engagement place can't be shaped, the torsion of its generation is better than in the past, and, even this body of rod is rolled over the tooth effect and produced the tissue variation, can not make this body of rod produce the crack, so the fraction defective on making reduces mutually over the ground yet.

In sum, the manufacture method of composite screws of the present invention has the manufacture process simplification really, torsion is better and the good effect of anti-corrosion property.

Claims (5)

1. A kind of manufacture method of composite screw comprises successively material preparation step, engagement step and rolles over the tooth step, and described material preparation step is formed separately out head with the mother metal of unlike material and without the body of rod of screw thread, it is characterized in that:

Described engagement step touches the body of rod in head bottom, and adopts friction welded method to engage, and makes the body of rod form the melting state with the end that contacts of head, and with this body of rod firm engagement bottom the head, form a composite screw embryo material;

Described rolling tooth step is rolled over tooth to the screw embryo material after processing through described engagement step, makes to present screw thread on the body of rod.

2. The manufacture method of composite screw as claimed in claim 1 is characterized in that:

After described rolling tooth step, comprise again a subsequent step;

Described subsequent step is that composite screw embryo material is heat-treated, electroplated.

3. The manufacture method of composite screw as claimed in claim 1 is characterized in that:

In described material preparation step, protrude a 6mm with interior round bar in the head bottom.

4. The manufacture method of composite screw as claimed in claim 1 is characterized in that:

The material of described head is stainless steel.

5. The manufacture method of composite screw as claimed in claim 1 is characterized in that:

The material of the described body of rod is carbon steel.

Images