yusak las

sarMATERI 2
WELDING PROCEDURE IMPLEMENTING, soldering, WITHHOLDING
WITH HEAT AND HEATING
(LAS MANUAL ARC)

A. UNDERSTANDING THE MANUAL ARC WELDING
Manual arc welding is a process of joining two pieces of metal or more, by melt it, use a bow that causes the two poles. One pole is connected to the workpiece, and one pole connected to the electrode.


Figure 3.1 Manual Arc Welding and Arc Welding
When the arc is formed, the temperature at the site of contact rises + 60000C. This heat is at the tip electrode. Metal melts together with the tip of the electrode, thus forming a small crater and there was a ridge-ridge welding.
At the same time, salutan / layer (flux) is also melting, providing a protective gas around the arc, and protect the liquid from the outside air. The speed of melting of the metal and the electrode is determined by a large electrical current (Ampere) applies.

B. MANUAL ARC WELDING EQUIPMENT
Manual arc welding equipment consists of main equipment, assistive devices and safety equipment.:
1. The main tools
a. Welding machine
Welding machine on the line in for the 3 groups, namely:
1) welding machines direct current (DC Welder)

Figure 3.2 DC Welding Machine with Petrol / Diesel And Welding Machine DC With Electricity
In general, direct current welding machines have a power source of direct current generator that in motion by motor gasoline, diesel and electric motors. Direct current welding machine most suitable for field work or for small workshops that do not have electricity network. Installation of welding wires in direct current welding machine can be adjusted / turned upside down in accordance with the purposes of welding, is expressly:

a) Direct Polarity (DCSP)

Figure 3.3 Polarity DCSP
With direct polarization, mean pole (+) welding machines connected to the workpiece. And polar (-) with a wire electrode. With this kind of relationship, heat welding occurring third electrode heats the heat, while two thirds of heating the workpiece.
b) Polarity reversed (DCRP)

Figure 3.4 Polarity DCRP
On the reverse polarization, polar (-) dihuibungkan welding machine with the workpiece. And pole (+) connected with the electrodes. In this kind of relationship, heat welding happens 1 / 3 part heat heats the workpiece and 2 / 3 the heating electrode. Election DCSP poles depends on:
Materials welded
Welding Position
Type of electrode used
The desired penetration
Changes in direct relationship to the polarization of the polarization inverted, or vice versa, simply by changing the position of the switch (S and R). This switch is normally the case in DC welding machine. So we do not have to change the position of the electrode wires and cables workpiece.
In direct current welding machine, regulating the flow usually is equipped with two kinds of regulators, namely: High and Low
The advantages of welding machines, DC, among others:
a) arc stable flame
b) Can use electrodes covered and not covered
c) Can welding thin plates in relation DCRP
d) Can be used in the field when using generators powered by diesel or gasoline engines
e) Can be used in workshops that do not have electricity network
The weakness of DC welding machines, among others:
a) The equipment is expensive and complicated
b) The conservancy is more complex
c) For DC welding machine power source of electric jarinagn, can not be used in the field
d) His voice is noisy and pollution occurs
2) welding machines alternating current (AC Welder)
Welding machine alternating current voltage is actually the step-down transformer. Voltage required by various welding machines. Typically 110 V, 220 V, 380 V or 440 V. Welding current settings can be done by rotating the handle, pull or push. Depending on the construction used, so that the position of the core's magnetic field shifted up and down on the transformer (travo)
In alternating current welding machine, the exchange did not affect the heat changes that occur in the arc flame.
a) The open voltage
In travo welding, signed at lower voltage around 45-80 V. This voltage is called voltage open, before the arc.
b) Voltage closed
When the electrodes in contact with the workpiece, will happened arc welding and the voltage will drop about 20-35 V. This voltage is called voltage closed.
Instalas welding machine:
a) Place the welding machine as near as possible to the current source, to obtain a short primer cord. This is very dangerous because the primary cable has a high voltage.
b) Check all cables from damage
c) Connect the workpiece and wire electrode into a welding machine, then plug the cable into the primary current source. Connecting the welding machine to the current source must pass through the outlet (switch off) and fuse)
d) Turn the power off (switch off) before other supplies complete
e) Clean the parts of the cable connecting the desk or the cable connecting the electrode and Tighten the connection of the loose parts that can cause high heat
f) Use all of which have cable insulation
g) Avoid clamp electrode from the desk, hang it on the insulated hanger
Benefits AC welding machines compared to DC welding machine, including:
a. Cheaper price
b. Higher work efficiency
c. Maintenance is easier
Weakness:
a. Can not be used in the field
b. Unstable arc
c. Heat distribution unchanged
b. Welding cable
The use of welding wire is influenced by the length of cable to be used and strong currents (Ampere). The longer the cable and ampernya large, then the greater the cord cross-sectional area. Welding cable there are 2 kinds:
1) primary cable: the cable that connects to a welding machine power source
2) secondary cable: Cable used for the electrodes and heat
c. Electrode
In general there are 2 types of electrodes, namely:
1) electrode coated (there is material that encloses the core wire welding)
2) Electrodes not plated
The function of salutan electrode:
1) Ease of maintenance arc flame
2) Tying the waste into slag
3) Protect the liquid metal from the influence of outside air oxidation
4) Helping to improve the composition of the liquid metal
Settings ampere (current) depends on:
1) diameter electrode
2) Type of electrode
3) Polarity
4) Thickness of material
5) The position of welding
As a rule in practice can use the following table:
Ampere Diameter Electrode Polarity
2.6 45-90 AC / DC
3.2 60-130 AC / DA -, +
4.0 90-160 AC / DC

d. Pliers (tongs) electrode
Is a tool used to clamp electrodes during the welding process
e. Tang j (penepit) period
Is a clamp used to clamp the workpiece, or iron table pedestal where the workpiece
2. Assistive devices
a. Slag hammer
b. Steel wire brush
c. Tools clamp workpieces
d. Measuring tools, drawing and cutting tools
3. Safety tools
a. Mask (mask) welding
b. Safety glasses
c. Clothing welding (wearpack)
d. Lapis dad (apron) or a welding jacket
e. Leather gloves
f. Las Shoes

C. WELDING PROCESS
1. How ignition electrode
a. How to touch / jolt
Is how to turn on the electrode with the way in touch straight for the object, then raised a distance + 1 x diameter electrode. Further on down again at a distance of 0.8 x the diameter of the electrode. Typically used in DC welding

Figure 3.5 How To Touch And How To Scratch

b. How to scratch
Is how to turn on the electrode by way of scraping the electrode on the workpiece (another metal). As soon as his bow lights, keep straight on 0.8 x diameter electrode
2. How to make a ridge-ridge las
a. After the electrodes on, we keep a distance of 0.8 x the diameter of the electrode from the working substance.
b. Electrodes are on leave quietly (do not shear-shear at first) to form a crater (pool) liquid metal + 80-10 mm.
c. After the resulting crater, then start a movement to make welding ridge-ridge (zig zak, circular or other) in berlahan-land.
The liquid metal from the electrode should not be interrupted, for ridge-ridge that forms can be organized. Please note that:
a. Electrodes should not be too high or too low
b. Raising the electrode / penggeserannya should not be too quick. Electrode shift distance in try + 1-2 mm
c. Electrodes are not in the pull back, but follow the way like the following picture (swing electrode)

Figure 3.6 Movement of Electrodes
3. Effect of ridge-ridge-making that is not appropriate
a. Electrode is too high
1) Rigi-rough ridge las
2) A copy of shallow lasnya
3) sparks rough and off the track welding
b. Electrode is too low
1) Rigi-rugged ridge
2) A copy lasnya not good
3) Sprinkle coarse lasnya spherical,
c. Electrodes too fast ascending / sliding
1) A copy of shallow lasnya
2) Welding is not kuats
d. Electrode is too slow
1) If the object is thin, will be broken or damaged
2) Line-riginya ridge width and the strong
4. Effect of incorrect amperage settings
a. Ampere is too small
1) ignition difficult
2) electric arc is unstable
3) The heat is not enough to melt the electrode and workpiece materials
4) A copy of shallow lasnya
b. Ampere is too big
1) The electrode melts too fast
2) Rigi-wide ridge lasnya
3) A copy lasnya sometimes too deep
5. Changes in shape (deformation)
a. Change happens because bentul
1) Construction Plan
2) The form seam
3) Hot welding
4) charging solution
5) Type of material
6) assembly procedure
7) How to setup
b. How to prevent deformation
1) Welding little as possible but face strong
2) Welding is done intersect
3) Make a ridge-ridge which led forces cancel each other out
4) Make a weld bonding (welding note) first