JOINTS PROSES MANUFAKTUR I
MACAM-MACAM SAMBUNGAN Las
Paku keling Baut Lem
Sambungan Las
Definisi Las LAS ADALAH IKATAN METALURGI PADA SAMBUNGAN LOGAM ATAU LOGAM PADUAN YANG DILAKSANAKAN DALAM KEADAAN LUMER ATAU CAIR - DIN -
Macam – Macam Pengelasan Pengelasan cair
Pengelasan tekan Pematrian
Welded Joints Design Butt joint
Corner joint Edge joint Lap joint
Tee joint
Butt Joints Bevel Groove
Square Groove
J Groove
U Groove
Vee Groove
Corner Joints
Open Corner
Closed Corner
1 2 3
1
4
2
Some considerations in selecting a type of joint to use on a fabrication Accessibility for welding
Strength requirements Cyclic or static loading Material thickness
Welding process to be used Material type Code Requirements Cost
Weld Quality (Size) Actual Throat
Effective Throat
Convexity Leg Size2 Leg Size1 Theoretical Throat
Weld Quality After selecting specified size gauge from set, measure Leg1
Measure Leg2 Verify throat with other side of gauge (face of gauge should touch weld)
L1
3/8
L2
Weld Quality (Fault) Undercut – most predominant weld fault ◦ Fix: Short arc length, proper amperage and speed
Weld Quality (Fault)
Weld Quality (Fault) Porosity: Lack of shielding gas Wet electrode Greasy material
Weld Quality (Fault) Slag Inclusion: Improper cleaning / removal of slag
Welding Joint Design & Welding Symbols – Chapter #5
Weld Quality - Review Undercut Porosity
Poor Fitup
Lack of Penetration
Weld Position (Plate) F = Fillet G = Groove 1 = Flat 2 = Horizontal 3 = Vertical 4 = Overhead
Weld Position (Pipe) G = Groove 1 = Horizontal Rolled 2 = Vertical 5 = Horizontal Fixed 6 = 45 Incline
Welding Symbols
3 parts of the welding symbol body:
Reference Line Tail Arrow
Weld Location Welding symbols ◦ Applied to reference line at the base ◦ Reference lines have an arrow side (near side) and other side (far side)
FIGURE 5-17 Designating weld location. American Welding Society
Sambungan Mur - Baut
Nuts and Bolts Threaded Fastener Issues:
Types Materials/Grades Tightening Torque
Threaded Fasteners Did you know that?
the Boeing 747 uses about 2.5 million fasteners ◦ 70,000 titanium costing $150,000 ◦ 400,000 other fasteners costing about $250,000 ◦ 30,000 squeeze rivets, 50cents each installed
In certain applications (such as an engine head), you should tighten the bolt as much as possible, if it does not fail by twisting during tightening, there is a very good possibility that the bolt will never fail
Why are fasteners used? Advantages
Removable Easy to install Wide variety of standard parts
Disadvantages loosening failure cost
Types Machine screws
Wood screws
Tapping screws
Standard Thread Systems Unified or American
ACME
SI (ISO)
Pipe
Whitworth (UK)
Typical Designation 1/2” - 13
UNC - 2 A external thread (B means internal)
Terminology of screw threads Sharp vee threads shown for clarity; the crests and roots are actually flattened or rounded during the forming operation.
Class of fit (1 is loosest tolerance, 3 is tightest) Thread Series UNC (Unified Coarse) UNF (Unified Fine) Pitch (threads/inch) Nominal Diameter (also shown as decimal or screw #)
Bolt Grades Grade indicates the tensile strength of the bolt
Determined by bolt material and heat treating
Tightening Torque It is typical on engines for bolts to have a specified tightening torque. Why?
It results in a quantified preload on the bolts Insures that parts never separate Maintains friction (no sliding to shear forces)
Insures even distribution of loading ◦ prevent warpage of mating parts ◦ uniform pressure distribution over seal or gasket
Prevents bolt from loosening
Reduces fatique effects
Bolt Manufacturing Processes Forging (upsetting)
Rolling a)
b)
Thread-rolling processes: a) reciprocating flat dies; and b) two-roller dies. Threaded fasteners, such as bolts, are made economically by these processes at high rates of production
Manufacturing Processes - continued Turning on screw machines
(a) Differences in the diameters of machined and rolled threads. (b) Grain flow in machined and rolled threads. Unlike machining, which cuts through the grains of the metal, rolled threads have improved strength because of cold working and favorable grain flow.
Sambungan Paku Keling
Sambungan paku keling Bagian-bagian paku keling
Pemasangan paku keling
Sambungan paku keling Standard: AISC (American Institute Steel Construction) ASME (American Society of Mechanical Engineers) Parameter Desain: Diameter
Material Desain: Menurut Indian Standard, IS : 2998-1982 (ditetapkan 1992), Tensile strenght > 40 N/mm2 Elongation = 26 % Keling dibuat dengan cold heading atau hot forging.
Sambungan paku keling Aplikasi:
Sambungan kuat dan rapat, pada konstruksi boiler ( boiler, tangki dan pipa-pipa tekanan tinggi ) Sambungan kuat, pada konstruksi baja (bangunan, jembatan dan crane ) Sambungan rapat, pada tabung dan tangki (tabung pendek, cerobong, pipa-pipa tekanan) Sambungan pengikat, untuk penutup chasis (mis ; pesawat terbang)
Sambungan paku keling Kelebihan:
Tidak akan longgar karena adanya getaran atau beban kejut Relatif murah dan pemasangan yang cepat Ringan Lebih tahan korosi dibandingkan sambungan baut Kekuatan fatigue lebih baik dari sambungan las Sambungan keling lebih sederhana dan murah untuk dibuat. Pemeriksaannya lebih mudah Sambungan keling dapat dibuka dengan memotong kepala dari paku keling tersebut.
Sambungan paku keling Kelemahan:
Tidak dapat dilepas Pencekaman tidak sekencang sambungan baut
Tipe kepala keling Kepala keling secara umum (di bawah diameter 12 mm)
Tipe kepala keling Kepala keling secara umum (diameter 12mm sampai 48mm)
Tipe kepala keling Kepala keling untuk ketel
Tipe sambungan keling Lap Joint (sambungan 2 lapis)
Tipe sambungan keling Lap Joint (sambungan 2 lapis)
Tipe sambungan keling Butt Joint (sambungan 3 lapis)
Kegagalan sambungan keling Keretakan pada sudut plat
Retak pada seluruh plat Pergeseran keling Perubahan bentuk (crushing) pada plat atau keling
Cara Pemasangan Paku Keling
