Hand welding practice problem_iv - Edwards @ Wiki

4 Weld state

Question 4.1 Terminology in welding conditions

1. Blowhole: Contaminated gas in weld metal in used gas
2. Hume: gas generated with welding
3. Slag: Nonmetal attached to weld metal surface
4. Weldability: proper welding of base metal

Question 4.2 Terms in welding state

1. Slag: Generating mixture against melting in welding
2. Undercut: Generation groove due to welding operation failure along the joining end
3. Penetration: Fusion depth to weld back side
4. Overlap: weld metal deposition state with respect to base metal

Question 4.3 Terms in the welding direction vertical section

1. Route surface: groove part perpendicular to the back surface of welding
2. Route interval: distance between route planes
3. Groove angle: Angle between mutual equalization planes before melting in mutual groove
4. Bevel angle: angle relative to the melt uniform plane with respect
   to the end portion of the route surface welding
5. Surplus: excessive weld metal on weld surface

Question 4.4 Terms for fillet welding
Leg length: The distance between each bonding base material
to each final welded toe end portion

Question 4.5 Weld symbols etc. on metal piping and board

1. Welding method
2. Leg length
3. Perimeter welding
   Note:
   Theoretical thickness: The shortest dimension from the root surface
   to the triangular surface formed by fillet welding
   Actual thickness: The shortest dimension up to the wall thickness of the final welded part
   of the welded part including the penetration part in fillet welding

Question 4.6 Weld Symbols and Names

1. V: V-shaped groove
2. Les: Type-opening destination
3. △: fillet fillet
4. I + ▲: Field welding

Question 4.7 Pressure resistance against fillet weld area with respect
to vertical horizontal plane Pressure descending order

1. Pressurized fillet weld to front and back surfaces
2. Fillet weld to pressurized surface
3. Fillet weld to pressure backside

Question 4.8 Types of welded joints

1. Butt joint
2. T joint
3. Lap joint
4. Crosscurrent joint
5. Rim joint

Question 4.9 Preparation before welding operation

1. Coating peeling and degreasing of the groove
2. Secure accurate route spacing for ensuring good backwave welding
3. Secure proper groove angle according to plate thickness

Question 4.10 Distortion generation rate by junction type: descending order

1. V type
2. I type
3. X type

Question 4.11 Construction for welding symbols

1. Conversely to the displayed numerical value of the sign leader

Question 4.12 Construction for welding symbols

1. Construction in order of numeric symbols on the back side
   of the vertical axis with respect to the leader line

Question 4.13 Construction for welding symbols
ex: I type joint: Double line is added to the leader line
and also to the opposite side of the leader line for construction on the front and back sides

Question 4.14 Construction for welding symbols

1. omission

Question 4.15 Weld state

1. Secure an accurate route spacing for striking welding

Question 4.16 Advantages of using welding jigs

1. Changing welding posture and ensuring dimensional accuracy
2. Ensure efficiency and quality improvement

Question 4.17 Measures against damage to welds

1. Crack: Prevention and countermeasures by post-heating
2. Distortion: Form distortion in the opposite direction and take countermeasures

Question 4.18 Deformation measures against welding

1. Formation of inverse strain
2. Suppression by constraint jig
3. Suppression by proper welding sequence

Question 4.19 Measures to prevent penetration in both side butt welding

1. Complete penetration is realized by back side welding in addition to fishing

Question 4.20 Residual stress

1. Measures against residual stress by post heat treatment
2. Residual stress is also generated against constraint of welding object by jig etc.

Question 4.21 Surplus in welding

1. Distortion expands against expansion of surplus

Question 4.22 Thickness

1. Omission

Question 4.23 Mechanical drawing symbol

1. Numerical values of the leader line: sheet thickness - route plane & route plane

Question 4.24 Mechanical drawing symbol

1. Attention to the numerical reading interpretation above and below the leader line
2. Interpret upper part fraction from lower part number

Question 4.25 Thickness

1. Omission

Question 4.26 Advantages of welding using jigs

1. Improve product accuracy
2. Easy to ensure high reliability
3. Improvement of work efficiency

Question 4.27 Measures against deformation caused by welding

1. Measures to be taken with constraint jig

Question 4.28 Points to be noted in tack welding

1. Measures against failure occurrence due to preheating of thick plates,
   low alloy steel and cool cold environment

Question 4.29 end tab

1. Prevent excess flow of weld metal by this part

Question 4.30 Tack welding

1. Omission

Question 4.31 Construction of tack welding

1. Avoid construction on corners and stress concentrating parts
2. In situations where preheating is required, welding
   at a higher temperature than the main welding

Question 4.32 Welding phenomenon due to excessive current

1. Sputtering occurs
2. Bar baking occurs due to resistance of welding rod
3. Easy to undercut

Question 4.33 Welding phenomenon due to under-current

1. Overlap occurs
2. Slag entrainment occurred
3. Weld defect occurred

Question 4.34 Measures against low temperature cracks in welding

1. Preheating and post-heating installation
2. Use of a fully dried low-hydrogen type welding rod
3. Appropriate welding procedure for residual stress generation

Question 4.35 Construction of preheating as a countermeasure against welding failure

1. Countermeasures against cracks caused by curing
2. Promotes removal of steel encapsulated hydrogen

Question 4.36 Types of welding defects

1. blow hole
2. Sludge entrapment
3. undercut
4. Overlap
5. crack
6. Merging problem
7. Penetration defect

Question 4.37 Effect on use of tab plate / end tab

1. Prevents flowing defects of molten metal against the beginning end
   in welding direction

Question 4.38 Effect on use of backing metal

1. Promotion of reliable penetration of molten metal
2. Prevents outflow of excess molten metal to the backside of welding

Question 4.39 Dealing with supplemental welding

1. Proper removal of poorly welded parts
2. Prevent contraction against short interval welding
3. Selection of supply welding medium diameter for reweld portion
4. After considering the cause countermeasure against cracks