Thread Content
Basic knowledge of screws Terminology related to screws 1. The difference between screws, nuts, nuts, bolts, screws and studs: The standard statement is that there are no screws and nuts. Screws are commonly known as screws, and anything with an external thread can be called a "screw". The nut is usually hexagonal in shape, and the inner hole is internally threaded, used to match the bolt and tighten the related parts. Nut is a common name, and the standard should be called "nut". The head of the bolt is generally hexagonal and the shaft has external threads. The screws are smaller, with flat heads, cross heads, etc., and external threads on the stem. Studs are actually called "double-ended studs", with external threads on both ends and a polished rod in the middle. The long end of the thread is used to connect to the deep hole, and the short end is connected to the nut. 2. Common English expressions: Screw / Bolt / Fastener (Screw/Screw) (Bolt) (Fastener) 3. Definition of thread: A thread is a shape with uniform spiral ridges on the outer or inner surface of a solid. * R: I7 r7 thread function 1. Fastening and connection function: Applicable to most screw products at this stage. 2. Transmission effect (displacement effect): Such as the micrometer used by QC to check dimensions. 3.Sealing effect: Such as pipe connection sealing. History of Thread Development Machine Thread: When assembling, first drill holes and tap holes in the assembly. The inner teeth to be tapped have the same specifications as the outer teeth of the screw, and a smaller torque is used for assembly. http://5b0988e595225.cdn.sohucs.com/images/20190613/eaf899e7279a4e0ab7e04b95b9fd7223.jpeg self tapping thread: When assembling, drill holes in the assembly first, without tapping the inner teeth, and use a larger torque to assemble. http://5b0988e595225.cdn.sohucs.com/images/20190613/207554b2148545e9b08e1f8f1e1474e9.jpeg self drilling thread: Use it directly on the assembly, screw drilling and tapping to form it in one step. http://5b0988e595225.cdn.sohucs.com/images/20190613/0bb45f61f4aa47fb9caa25d2cf5f6730.jpeg Screw processing method 1. Turning (Turning) uses the method of removing material to make the material achieve the desired shape.: High processing accuracy and no mold restrictions: The production cost is high and the processing speed is slow. 2. Forging uses external force to squeeze the material to deform it to achieve the desired shape.: Fast production speed, low cost, suitable for mass production: Forming is limited by molds, and mold costs for complex products are high 3. Cold heading: It is a process in which the metal wire is extruded and deformed by using external force without heating. The cold heading process is just a type of forging process. Introduction to the basic configuration of screws. To understand screws and bolts, you must first know their types, characteristics and functions.: A: Driving system B: Head C: Teeth-type joint part D: Introduction and penetration part http://5b0988e595225.cdn.sohucs.com/images/20190613/526736722530425ba9e25aff7b2b2123.jpeg Mechanical thread screws http://5b0988e595225.cdn.sohucs.com/images/20190613/4e015a21d8ab4e2f9b3f44f4d029ee3e.jpeg self tapping screws http://5b0988e595225.cdn.sohucs.com/images/20190613/8364f52564b7407b882fa5094281349d.jpeg Triangular thread screw http://5b0988e595225.cdn.sohucs.com/images/20190613/d56de367e04d431ba3513cce20356642.jpeg Screw head type http://5b0988e595225.cdn.sohucs.com/images/20190613/3dacd0e1537b474ca2eebbe09f3b7433.jpeg Screw tooth type http://5b0988e595225.cdn.sohucs.com/images/20190613/cdcaa4284c214c3b866d5fd24990abce.jpeg' Q4 o4 N) z& g2 Y+ T3 y) W The general flow chart of the screw process is as follows: http://5b0988e595225.cdn.sohucs.com/images/20190613/afaea320b8ff4ff49395a5946cc63104.jpeg The plate unit process# a6 O @6 q- u3 O. E9 r refers to the original wire rod purchased by the raw material manufacturer. A plate unit mainly includes the following parameters: A. Brand B. Product name C. Specification D. Material E. Furnace number or batch number F. Quantity or weight. The main chemical components of carbon steel disc elements are: C, Mn, P, S, Si, Cu, Al, among which the lower the content of Cu and Al, the better. http://5b0988e595225.cdn.sohucs.com/images/20190613/65552af0442d4a8aafc619060ef9af62.jpeg Wire drawing process" `5 b F- b# Z$ D2 O In order to achieve the wire diameter we need (such as 3.5mm wire drawing). http://5b0988e595225.cdn.sohucs.com/images/20190613/9ff16be4af0d413ab6c07a7eddcb2883.jpeg The cold heading (heading) process uses the interaction between molds to shape it. The wire is first cut, and the screw blank is formed into a head, cross recess (or other head shape), thread blank diameter and rod length, rounded corners under the head, etc. http://5b0988e595225.cdn.sohucs.com/images/20190613/bf242774410b4549b395be2259998ee1.jpeghttp://5b0988e595225.cdn.sohucs.com/images/20190613/9dca71de882047b79ef54169b791b739.jpeg illustrate: It can be designed according to the needs of customers. Commonly used head types are P head, B head, F head, T head, etc. Commonly used groove types include cross groove, straight groove, plum blossom groove, inner hexagonal groove, etc. http://5b0988e595225.cdn.sohucs.com/images/20190613/d8c372988eb343078be9422e7fdcba35.jpeghttp://5b0988e595225.cdn.sohucs.com/images/20190613/43a858dabb744f45a7141dfe9a29a908.jpeg Thread rolling process' R& ^6 J+ R# R' s The cold-forged blank is threaded, and the thread is formed through the interaction between the movable die plate and the fixed die plate. Teeth rubbing process http://5b0988e595225.cdn.sohucs.com/images/20190613/d72dbca1a60342e09f07a7947c3c9d7d.jpeg Changes before and after tooth rubbing http://5b0988e595225.cdn.sohucs.com/images/20190613/a3496019c9e44d84a41d0a88b63b7c01.jpeg Teeth rubbing machine http://5b0988e595225.cdn.sohucs.com/images/20190613/7414dc21b850408da2b7cbd3f6b0aba3.jpeg Washing board (template) http://5b0988e595225.cdn.sohucs.com/images/20190613/41d9d3cc74fc44aaa0a1b1df15076125.jpeg Heat treatment process 1. Purpose: In order to make the screws obtain higher hardness and strength after cold heading. 2. Function: Achieve self-tapping locking of metal and improve the mechanical properties of metal parts, such as torsion resistance, tensile resistance, and wear resistance. 3. Classification: A. Annealing: (700℃x 4hr): Elongated tissue - regular polygonization. http://5b0988e595225.cdn.sohucs.com/images/20190613/9cce52ac77ea473292c4104f50eaf10f.jpeg Cold working structure morphology B. Carburizing heat treatment (adding carbon elements to metal parts to improve their surface hardness, for metal materials with low carbon content). http://5b0988e595225.cdn.sohucs.com/images/20190613/e774d4b8b66d4c4b99c1c3851b1001f0.jpegC. Quenching and tempering heat treatment (without adding elements to the metal, using temperature changes to change the internal structure of the metal to obtain better mechanical properties). http://5b0988e595225.cdn.sohucs.com/images/20190613/cddbc1fae5f7429ea53b7db65ebff68b.jpeg The surface of the product after electroplating process can show the required color effect and surface anti-oxidation coating effect. http://5b0988e595225.cdn.sohucs.com/images/20190613/65248e07829e42f0807881d772ebeaec.jpeghttp://5b0988e595225.cdn.sohucs.com/images/20190613/a6ee6c35e2af42f79745ef1e1228268d.jpeg' n4 y2 a `. n: u( } ~- e: k Attachment: Screw standard parts query table Screw size range dl Machine screws Slotted cylindrical head screws GB/T65-2000M1.6～M102～80 Slotted pan head screws GB/T67-2000M1.6～M102～80 Slotted countersunk head screws GB/T68-2000M1.6～M102.5～80 Slotted countersunk head screws GB/T69-2000M1.6～M102.5～80 Cross recessed pan head screws GB/T818-2000M1.6～M1025～40 Cross recessed countersunk head screws GB/T819.1-2000M1.6～M1030～45 Cross recessed countersunk head screws GB/T820-2000M1.6～M1030～45 Cross recessed cylindrical head screws GB/T822-2000M1.6～M1020～40 Cross recessed small pan head screws GB/T823-2000M1.6～M1020～50 Cross recessed countersunk head screws GB/T819.2-2000M2～M103～60 Cross recessed screws for precision machinery GB/T13806.1-1992M1.2～M31.6～10 Slotted spherical cylindrical head screws with holes GB/T832-1988M1.6～M102.5～60 Slotted large cylinder head screws GB/T833-1988M1.6～M102.5～20 Slotted spherical large cylinder head screws GB/T947-1988M1.6～M102～20 Hexagonal socket head screws GB/T2671-2004M6～M2010～120 Hexalobular pan head screws GB/T2672-1986M6～M208～80 Hexalobular countersunk head screws GB/T2673-1986M6～M208～80 Hexalobular countersunk head screws GB/T2674-1986M6～M208～80 Hexalobular cylindrical head screws GB/T6190-1986M6～M208～80 Set screws Slotted tapered end set screws GB/T71-1985M1.6～M122～60 Slotted flat end set screws GB/T73-1985M1.6～M122～60 Slotted concave end set screws GB/T74-1985M1.6～M122～60 Slotted long cylindrical end set screws GB/T75-1985M1.6～M122.5～60 Hexagon socket flat end set screws GB/T77-2000M1.6～M242～60 Hexagon socket cone end set screws GB/T78-2000M1.6～M242～60 Hexagon socket cylindrical end set screws GB/T79-2000M1.6～M242～60 Hexagon socket concave end set screws GB/T80-2000M1.6～M242～60 Square head long cylindrical spherical end set screw GB/T83-1988M8～M2016～100 Square head concave end set screw GB/T84-1988M5～M2010～100 Square head long cylindrical end set screw GB/T85-1988M5～M2012～100 Square head short cylindrical tapered end set screws GB/T86-1988M5～M2012～100 Square head flat end set screws GB/T821-1988M5～M208～100 Hexagon socket head screws GB/T70.1-2000M1.6～M482.5～300 Hexagon socket head screws GB/T70.2-2000M3～M166～50 Hexagon countersunk head screws GB/T70.3-2000M3～M208～100 Hexagon socket head screws GB/T6191-1986M6～M2010～80 Positioning and axial screws Slotted cone end positioning screws GB/T72-1988M1.6～M124～50 Slotted cylindrical end positioning screws GB/T829-1986M1.6～M101.5～20 Slotted pan head positioning screws GB/T828-1988M1.6～M101.5～20 Slotted cylindrical head screws GB/T830-1988M1.6～M101～20 Slotted headless axial screws GB/T831-1988M1.6～M101～20 Slotted spherical cylindrical head axial screws GB/T946-1988M1.6～M102～20 Non-Protruding Screws Slotted Pan Head Non-Protruding Screws GB/T837-1988M3～M1010～60 Slotted Countersunk Head Non-Protruding Screws GB/T948-1988M3～M1010～60 Slotted Semi-Countersunk Head Non-Protruding Screws GB/T949-1988M3～M1010～60 Hexagonal head non-detachable screws GB/T838-1988M5～M1614～100 Knurled head non-detachable screws GB/T839-1988M3～M1010～60 Special screw eye screws GB/T825-1988M8～M100X66～140 Knurled high head screws GB/T834-1988M1.6～M102～35 Knurled flat head screws GB/T835-1988M1.6～M102～45 Knurled small head screws GB/T836-1988M1.6～M63～40 Plastic knurled screws GB/T840-1988M4～M163～40 Self-tapping screws Cross recessed pan head self-tapping screws GB/T845-1985ST2.2～ST9.54.5～50 Cross recessed countersunk head self-tapping screws GB/T846-1985ST2.2～ST9.54.5～50 Cross recessed semi-countersunk head self-tapping screws GB/T847-1985ST2.2～ST9.54.5～50 Slotted pan head self-tapping screws GB/T5282-1985ST2.2～ST9.54.5～50 Slotted countersunk head self-tapping screws GB/T5283-1985ST2.2～ST9.54.5～50 Slotted countersunk head self-tapping screws GB/T5284-1985ST2.2～ST9.54.5～50 Hexagonal head self-tapping screws GB/T5285-1985ST2.2～ST9.54.5～50 Cross recessed hexagonal head self-tapping screws GB/T9456-1988ST2.9～ST86.5～50 Cross recessed self-tapping screws GB/T13806.2-1992ST1.5～ST84.5～25 Self-tapping locking cross recessed pan head self-tapping locking screws GB/T6560-1986M2～M64～60 Cross recessed countersunk head self-tapping locking screws GB/T6561-1986M3～M66～60 Cross recessed semi-countersunk head self-tapping locking screws GB/T6562-1986M3～M66～60 Hexagon socket self-tapping locking screws GB/T6563-1986M5～M1210～80 Self-drilling self-tapping cross recessed pan head self-drilling self-tapping screws GB/T5856.1-2002ST2.9～ST6.313～50 Cross recessed countersunk head self-drilling self-tapping screws GB/T5856.2-2002ST2.9～ST6.313～50 Cross recessed semi-countersunk head self-drilling self-tapping screws GB/T5856.3-2002ST2.9～ST6.313～50 Wood screws Slotted round head wood screws GB/T99-19861.6～106～120 Slotted countersunk head wood screws GB/T100-19861.6～106～120 Slotted semi-countersunk head wood screws GB/T101-19861.6～106～120 Hexagon head wood screws GB/T102-19862～2035～120 Cross recessed round head wood screws GB/T950-19862～106～120 Cross recessed countersunk head wood screws GB/T951-19862～106～120 Cross recessed countersunk head wood screws GB/T952-19862～106～120