Zavaruvanje Brosura
Zavaruvanje Brosura
Zavaruvanje Brosura
July 2005
Processes
Stick (SMAW) Welding
www.MillerWelds.com
TABLE OF CONTENTS
SECTION 1 SAFETY PRECAUTIONS - READ BEFORE USING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1. Symbol Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2. Arc Welding Hazards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3. Additional Symbols For Installation, Operation, And Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4. California Proposition 65 Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5. Principal Safety Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6. EMF Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SECTION 2 PRINCIPLES OF SHIELDED METAL ARC WELDING (SMAW) . . . . . . . . . . . . . . . . . . . . . . . . . SECTION 3 SHIELDED METAL ARC WELDING (SMAW) PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1. Typical Stick Welding Set-Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2. Electrode And Amperage Selection Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3. Striking An Arc Scratch Start Technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4. Striking An Arc Tapping Technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5. Positioning Electrode Holder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6. Electrode Movement During Welding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7. Conditions That Affect Weld Bead Shape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8. Poor Weld Bead Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9. Good Weld Bead Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10. Typical Weld Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11. Welding Butt Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12. Welding Tee Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13. Welding Lap Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14. Welding Horizontal Beads And Butt Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15. Welding Vertical Beads And Butt Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-16. Welding Vertical Tee Joints And Lap Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17. Welding Overhead Butt Joints And Tee Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-18. Weld Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SECTION 4 WELDING TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1. Porosity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2. Excessive Spatter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3. Incomplete Fusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4. Lack Of Penetration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5. Excessive Penetration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6. Burn-Through . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7. Waviness Of Bead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8. Distortion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 1 3 3 4 4 5 6 6 7 8 8 9 10 11 12 12 13 14 15 15 16 17 18 19 20 20 20 21 21 21 22 22 22 22
Y Warning: Protect yourself and others from injury read and follow these precautions.
D D D D D D D D D D D D
Turn off all equipment when not in use. Do not use worn, damaged, undersized, or poorly spliced cables. Do not drape cables over your body. If earth grounding of the workpiece is required, ground it directly with a separate cable. Do not touch electrode if you are in contact with the work, ground, or another electrode from a different machine. Do not touch electrode holders connected to two welding machines at the same time since double open-circuit voltage will be present. Use only well-maintained equipment. Repair or replace damaged parts at once. Maintain unit according to manual. Wear a safety harness if working above floor level. Keep all panels and covers securely in place. Clamp work cable with good metal-to-metal contact to workpiece or worktable as near the weld as practical. Insulate work clamp when not connected to workpiece to prevent contact with any metal object. Do not connect more than one electrode or work cable to any single weld output terminal.
SIGNIFICANT DC VOLTAGE exists in inverter-type welding power sources after removal of input power.
D Turn Off inverter, disconnect input power, and discharge input capacitors according to instructions in Maintenance Section before touching any parts.
READ INSTRUCTIONS.
D Read Owners Manual before using or servicing unit. D Use only genuine Miller/Hobart replacement parts.
D D
D D
D High-frequency (H.F.) can interfere with radio navigation, safety services, computers, and communications equipment. D Have only qualified persons familiar with electronic equipment perform this installation. The user is responsible for having a qualified electrician promptly correct any interference problem resulting from the installation. If notified by the FCC about interference, stop using the equipment at once. Have the installation regularly checked and maintained. Keep high-frequency source doors and panels tightly shut, keep spark gaps at correct setting, and use grounding and shielding to minimize the possibility of interference.
D D D
D Electromagnetic energy can interfere with sensitive electronic equipment such as computers and computer-driven equipment such as robots. D Be sure all equipment in the welding area is electromagnetically compatible. To reduce possible interference, keep weld cables as short as possible, close together, and down low, such as on the floor. Locate welding operation 100 meters from any sensitive electronic equipment. Be sure this welding machine is installed and grounded according to this manual. If interference still occurs, the user must take extra measures such as moving the welding machine, using shielded cables, using line filters, or shielding the work area.
2 3 1 4
4
Ref. 157 858
Arc length is the distance from the electrode to the workpiece. A short arc with correct amperage will give a sharp, crackling sound. Correct arc length is related to electrode diameter. Examine the weld bead to determine if the arc length is correct. Arc length for 1/16 and 3/32 in diameter electrodes should be about 1/16 in (1.6 mm); arc length for 1/8 and 5/32 in electrodes should be about 1/8 in (3 mm). 7 Slag Use a chipping hammer and wire brush to remove slag. Remove slag and check weld bead before making another weld pass.
Tools Needed:
151 593
ELECTRODE
DIAMETER
100
150
200
250
AMPERAGE RANGE
300
350
400
6013
7014
7018
7024
1/8 5/32 3/16 7/32 1/4 3/32 1/8 5/32 3/16 3/32 1/8 5/32
Ni-Cl
308L
PENETRATION
ELECTRODE
POSITION
ALL ALL ALL ALL ALL FLAT HORIZ FILLET ALL ALL
MIN. PREP, ROUGH HIGH SPATTER GENERAL SMOOTH, EASY, FAST LOW HYDROGEN, STRONG SMOOTH, EASY, FASTER CAST IRON STAINLESS
*EP = ELECTRODE POSITIVE (REVERSE POLARITY) EN = ELECTRODE NEGATIVE (STRAIGHT POLARITY) Ref. S-087 985-A
USAGE
DC*
AC
450
50
. The
1 1 2 3
Drag electrode across workpiece like striking a match; immediately lift electrode slightly after touching work. If arc goes out, electrode was lifted too high. If electrode sticks to workpiece, use a quick twist to free it. 2
S-0049
Bring electrode straight down to workpiece; then lift slightly to start arc. If arc goes out, electrode was lifted too high. If electrode sticks to workpiece, use a quick twist to free it.
S-0049
10- 30
. To
90 90
produce the best results, hold a short arc, travel at a uniform speed, and feed the electrode downward at a constant rate as it melts.
Direction Of Welding
Fillet Welds
45
10- 30
45 Direction Of Welding
S-0660
.A
single stringer bead is satisfactory for most narrow groove weld joints; however, for wide groove weld joints or bridging across gaps, a weave bead or multiple stringer beads work better.
1 2 3
Stringer Bead Steady Movement Along Seam Weave Bead Side To Side Movement Along Seam Weave Patterns
Use weave patterns to cover a wide area in one pass of the electrode. Limit weave width to a maximum of 2-1/2 times diameter of electrode.
S-0054-A
Notes
Electrode Angle
Correct Angle 10
- 30
Drag
Arc Length
Spatter
Too Short
Normal
Too Long
Travel Speed
Too Slow
Normal
Too Fast
S-0661
S-0053-A
Weld a new bead or layer for each 1/8 in (3.2 mm) thickness in metals being welded. 4 5 1 No Overlap Good Penetration Into Base Metal
S-0052-B
Butt Joint
Butt Joint
Lap Joint
Tee Joint
Lap Joint
Tee Joint
Butt Joint
Butt Joint
Lap Joint
Tee Joint
Lap Joint
Tee Joint
Types Of Butt Joint Welds 1 1 Tack Welds Prevent butt joint distortion by tack welding the materials in position before final weld. Workpiece distortion occurs when heat is applied locally to a joint. One side of a metal plate will curl up toward the weld. Distortion will also cause the edges of a butt joint to pull together ahead of the electrode as the weld cools. 2 3 4 Square Groove Weld Single V-Groove Weld Double V-Groove Weld
Materials up to 3/16 in (5 mm) thick can often be welded without special preparation using the square groove weld. However, when welding thicker materials it may be necessary to prepare the edges (V-groove) of butt joints to ensure good welds. The single or double V-groove weld is good for materials 3/16 3/4 in (5-19 mm) thick. Generally, the single Vgroove is used on materials up to 3/4 in (19 mm) thick and when, regardless of thickness, you can weld from one side only. Cut the bevel with oxyacetylene or plasma cutting equipment. Remove scale from material after cutting. A grinder can also be used to prepare bevels. Create a 30 degree angle of bevel on materials in V-groove welding. Butt Joint Training Procedure Practice welding butt joints on 1/8 in (4 mm) or thicker material. (Avoid thinner materials since they require greater skill.) Separate the squared edges of the material about 1/16 in (1.6 mm) and make a butt weld all the way through with a 1/8 in electrode. (You may need to adjust the weld current and travel speed to obtain the desired weld.) Perform a similar exercise on 1/4 in (6 mm) material, depositing a bead on each side of the joint and fusing one to the another (no bevel needed). Practice making a single V-groove weld on 1/4 in (6 mm) plate beveled 30. Start with a 1/8 in electrode for the first bead and finish with a 5/32 in (4 mm) electrode. Be sure to penetrate about 1/32 in (1 mm) beyond the bottom of the V or root. Perform a similar exercise on thicker materials. Generally, deposit a bead for each 1/8 in (3mm) of material thickness, cleaning the joint between layers. On heavier plates, it may be necessary to weave the top layers to fill the groove. After completing the practice welds, test them as described in Section 3-18.
30
S-0662
45 Or Less
Keep arc short and move at definite rate of speed. Hold electrode as shown to provide fusion into the corner. Square edge of the weld surface. For maximum strength weld both sides of upright section. 3 Multi-Layer Deposits Weld a second layer when a heavier fillet is needed. Use any of the weaving patterns shown in Section 3-6. Remove slag before making another weld pass.
3
S-0060 / S-0058-A / S-0061
Move electrode in circular motion. Weld a second layer when a heavier fillet is needed. Remove slag before making another weld pass. Weld both sides of joint for maximum strength.
30 Or Less 1
S-0063 / S-0064
Direction Of Welding
90
Bevel edges if warranted by material thickness (see Section 3-11). Tack weld a backing strip to the plates to make the first weld pass (root pass) easier.
15
Single Pass Horizontal Butt Joint Weld Or First Pass Of Multi-Layer Deposit
2 30
30
Direction Of Welding
90
Direction Of Welding
30 Tilt Electrode 15 In Direction Of Travel Make First Weld Pass (Root Pass). Make Second Weld Pass.
45
Direction Of Welding
Completed Weld.
804 260
. When
1/2 in (12 mm) Direction Of Welding 1
welding vertically, gravity may distort the molten metal. suitable for all electrodes.
Direction Of Welding
90
Whipping Up Motion
Weld vertically by carrying the weld upward or starting at the top and welding down. Welding upward is easier and is shown in these illustrations. Bevel edges if warranted by material thickness (see Section 3-11). Tack weld a backing strip to the plates to make the first weld pass (root pass) easier.
Single Pass Vertical Butt Joint Weld Or First Pass Of Multi-Layer Deposit
90
Direction Of Welding
90
1st Pass 2nd Pass Hesitate With Slight Up And Down Motion. Shorten Arc At Arrowheads When At Center Of Weld. Direction Of Welding Direction Of Welding 4th Pass
OR
3rd Pass
804 260
. When
90
welding vertically, gravity may distort the molten metal. suitable for all electrodes.
For maximum strength, weld both sides of joint. Direction Of Welding 90 First Weld Pass Shows Weaving Motion. Direction Of Welding OR Direction Of Welding 90 Direction Of Welding 90 Subsequent Weld Passes Shows Weaving Motion.
90
804 260
. When
welding overhead, gravity may distort the molten metal. suitable for all electrodes.
Welding overhead is the most difficult welding skill to master. When welding overhead, use a welding motion that draws arc out and slightly away from the crater to allow weld puddle to solidify. When weaving is necessary, use the pattern shown. Bevel edges if warranted by material thickness (see Section 3-11). Tack weld a backing strip to the plates to make the first weld pass (root pass) easier.
Direction Of Welding
Draw arc out and away from crater to let weld puddle soldify.
Welding Patterns
Sequence Of Multiple Weld Passes Tee Joint Weld 1/2 in (12 mm)
Direction Of Welding
30
804 260
Strike the weld joint in the direction shown. A good weld bends over but does not break. 3 3 2 To 3 in. (51-76 mm) If the weld breaks, examine it to determine the cause. If the weld is porous (many holes), the arc length was probably too long. If the weld contains bits of slag, the arc may have been too long or the electrode was moved incorrectly which allowed molten slag to be trapped in the weld. This may happen on a V-groove joint made in several layers and calls for additional cleaning between layers. If the original beveled surface is visible the material was not fully melted which is often caused by insufficient heat or too fast a travel speed.
2 1
S-0057-B
Possible Causes
Arc length too long. Workpiece dirty. Damp electrode. Reduce arc length.
Corrective Actions
Remove all grease, oil, moisture, rust, paint, coatings, slag, and dirt from work surface before welding. Use dry electrode.
Possible Causes
Amperage too high for electrode.
Corrective Actions
Decrease amperage or select larger electrode.
Arc length too long or voltage Reduce arc length or voltage. too high.
Possible Causes
Insufficient heat input. Improper welding technique.
Corrective Actions
Increase amperage. Select larger electrode and increase amperage. Place stringer bead in proper location(s) at joint during welding. Adjust work angle or widen groove to access bottom during welding. Momentarily hold arc on groove side walls when using weaving technique. Keep arc on leading edge of weld puddle.
Workpiece dirty.
Remove all grease, oil, moisture, rust, paint, coatings, slag, and dirt from work surface before welding.
Lack of Penetration
Good Penetration
Possible Causes
Improper joint preparation. Improper weld technique.
Corrective Actions
Material too thick. Joint preparation and design must provide access to bottom of groove. Keep arc on leading edge of weld puddle. Reduce travel speed.
Excessive Penetration
Good Penetration
Possible Causes
Excessive heat input. Improper weld technique.
Corrective Actions
Select lower amperage. Use smaller electrode. Adjust travel speed.
4-6. Burn-Through
Burn-Through weld metal melting completely through base metal resulting in holes where no metal remains.
Possible Causes
Excessive heat input.
Corrective Actions
Select lower amperage. Use smaller electrode. Increase and/or maintain steady travel speed.
Possible Causes
Unsteady hand. Use two hands. Practice technique.
Corrective Actions
4-8. Distortion
Distortion contraction of weld metal during welding that forces base metal to move. Base metal moves in the direction of the weld bead.
Possible Causes
Excessive heat input.
Corrective Actions
Use restraint (clamp) to hold base metal in position. Make tack welds along joint before starting welding operation. Predict anticipated weld distortion and precamber base metal. Select lower amperage for electrode. Increase travel speed. Weld in small segments and allow cooling between welds.
Notes
MATERIAL THICKNESS REFERENCE CHART 24 Gauge (.025 in) 22 Gauge (.031 in) 20 Gauge (.037 in) 18 Gauge (.050 in) 16 Gauge (.063 in) 14 Gauge (.078 in) 1/8 in (.125 in) 3/16 in (.188 in) 1/4 in (.25 in) 5/16 in (.313 in)
Notes
Notes
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