Student Material 001: Weld Quality & Safety Quick Reference

Material ID: U6M4-MAT-001 Purpose: Quick reference for weld inspection criteria, defect identification, repair procedures, and shop safety Updated: 2026-03-19

7-Step Visual Weld Inspection Procedure

1. CLEAN — Wire brush the weld thoroughly
2. LIGHT — Use bright LED at an angle to reveal defects
3. PROFILE — Check overall bead shape, width, height
4. TOES — Inspect where weld meets base metal (undercut? cold lap?)
5. SURFACE — Look for porosity, pits, irregularities
6. CRACKS — Check weld center and toes for any cracking
7. MEASURE — Use fillet gauge, calipers for dimensional check

Acceptance Criteria Quick Reference

Fillet Welds

Criteria	Accept	Reject
Leg size	≥ minimum specified	Below minimum
Leg equality	Within 1/16" of each other	Differ by >⅛"
Undercut depth	≤ 1/32"	>1/32"
Porosity	≤ 3 pores/inch, each <3/32"	More or larger
Cracks	NONE	ANY
Cold lap/overlap	NONE visible	ANY visible
Reinforcement	Slight convexity OK	Excessive or concave

Butt Welds

Criteria	Accept	Reject
Reinforcement	0 to ⅛"	>⅛" or concave
Undercut	≤ 1/32"	>1/32"
Porosity	≤ 3 pores/inch	>3 pores/inch
Cracks	NONE	ANY
Misalignment	≤ 1/16"	>1/16"
Penetration	Full (visible on back)	Incomplete (structural)

Weld Defect Identification Guide

Defect	What It Looks Like	Most Common Cause	Fix
Porosity	Small holes/pits in or on weld surface	Contamination, gas issues	Clean metal, fix gas flow
Undercut	Groove along weld toe	Too hot, wrong angle	Reduce heat, adjust angle
Lack of Fusion	Weld sitting on surface, not bonded	Too cold, wrong angle	More heat, aim at root
Burn-through	Hole melted through base metal	Too hot for thickness	Reduce amps, go faster
Excessive Spatter	Metal balls around weld	V/WFS mismatch (MIG)	Adjust voltage
Crack	Linear discontinuity in or near weld	Rapid cooling, high carbon, restraint	Preheat, slow cool, crater fill
Excessive Reinforcement	Weld cap too tall (>⅛")	Too much filler, too slow	Speed up, reduce filler
Cold Lap/Overlap	Weld metal rolled onto surface without fusing	Too cold, too much filler	Increase heat, reduce filler
Incomplete Penetration	Root not fused (visible on back of butt joint)	Low amps, small root gap	Increase amps, widen gap
Tungsten Inclusion (TIG)	Hard spot in weld, may show on surface	Contaminated tungsten dipped in pool	Re-grind tungsten, better technique

Weld Repair Procedure

Step 1: IDENTIFY
├── Mark defect boundaries with soapstone
├── Add ¼" on each side
└── Document defect type and probable cause

Step 2: GRIND OUT
├── Put on grinding PPE (face shield, NOT welding helmet)
├── Grind to sound metal (complete removal)
├── Create a U-groove for weld access
├── For cracks: grind ¼" beyond visible ends
└── Smooth with flap disc

Step 3: CLEAN
├── Wire brush the ground area
├── Degrease with acetone
└── Verify complete defect removal (loupe inspection)

Step 4: RE-WELD
├── Start ¼" before the ground area (tie-in)
├── Fill the groove completely
├── End ¼" past the ground area (tie-in)
├── Apply crater fill technique
└── Use lower heat than original if burn-through was the defect

Step 5: RE-INSPECT
├── Full 7-step visual inspection
├── Apply same acceptance criteria
├── Document pass/fail
└── If fail: grind out and repeat (max 3 attempts)

Shop Safety Quick Reference Card

Emergency Equipment Locations

(Fill in for your specific shop)

Equipment	Location
Fire extinguisher(s)	_______
Eyewash station	_______
First aid kit	_______
AED	_______
Main power disconnect	_______
Emergency exits	_______
Assembly point	_______

Emergency Response Summary

Emergency	Step 1	Step 2	Step 3
Electrical shock	DO NOT TOUCH victim	Main breaker OFF	Call 911, CPR/AED
Severe burn	Remove from source	Cool water 20 min	Call 911 if serious
Fire (small)	Power off equipment	P.A.S.S. extinguisher	Evacuate if growing
Fire (large)	EVACUATE	Pull alarm	Call 911
Arc eye	Move to dim area	Cool compress	See doctor (6-12 hr delay)
Fume exposure	Fresh air	Call 911 if severe	Report material type
Cylinder leak	Close valve	Ventilate	Report to supervisor

Gas Cylinder Storage Rules

[✓] Stored UPRIGHT
[✓] Chained or strapped to wall/cart
[✓] Valve caps on when not in use
[✓] Fuel gases separated from oxidizers by 20 ft (or 5 ft fire wall)
[✓] Away from heat sources and electrical circuits
[✓] "Empty" and "Full" cylinders separated and labeled
[✗] Never store near exits, stairs, or elevators
[✗] Never drag, roll, or drop cylinders
[✗] Never use oil/grease on regulators

Welding Fume Exposure Limits (OSHA PEL)

Substance	PEL (8-hr TWA)	Source	Required Respiratory Protection
Iron oxide fumes	10 mg/m³	All steel welding	P100 half-face
Manganese fumes	5 mg/m³ (ceiling)	Most steel filler metals	P100 half-face
Hexavalent chromium	5 μg/m³	Stainless steel welding	P100 + OV, maximum ventilation
Zinc oxide	5 mg/m³	Galvanized steel	P100 + OV, grind coating first
Ozone	0.1 ppm	UV radiation from arc	Adequate ventilation

Welding Log Template

Date: _____________ Operator: _____________

Material: _____________ Thickness: _____________
Process: MIG / TIG     Filler: _____________
Gas: _____________ Flow: _____ CFH

MIG Settings:
  Voltage: _____ V    WFS: _____ IPM

TIG Settings:
  Amperage: _____ A   Polarity: DCEN / AC
  AC Balance: _____   AC Freq: _____

Joint Type: Butt / Lap / T / Corner / Edge
Position: Flat / Horizontal / Vertical / Overhead

Results:
  Bead Width: _____   Leg Size: _____
  Penetration: Full / Partial / None
  Defects Found: _________________________
  Pass / Fail

Notes: ___________________________________

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Last Updated: 2026-03-19