Material Identification, Handling, and Preparation

Identification, Handling, and Preparation of Materials

Module Introduction

This chapter covers all the knowledge required for the Red Seal exam concerning the identification of metals, their safe handling, and their preparation before welding or assembly. As a metal fabricator (fitter), you must not only know how to read material specifications, but also understand their physical and chemical properties, the standards that govern them, and the preparation procedures that ensure the integrity of assemblies. Mastering this content is essential: approximately 15 to 20% of the exam questions cover this competency area.

Identification of Ferrous Metals

General Classification of Steels

Steels are alloys of iron and carbon, with a carbon content generally below 2.11%. Beyond this value, the material is referred to as cast iron. The classification of steels is based on their chemical composition, their deoxidation method, and their mechanical properties.

Carbon Steels

Carbon steels are subdivided into four categories according to their carbon content:

Category	Carbon Content (%)	Typical Applications
Extra-mild steel	0.05 – 0.15	Sheet metal, tubes, wire, automotive body panels
Mild steel	0.15 – 0.30	Structural frames, tanks, beams
Medium-carbon steel	0.30 – 0.50	Shafts, gears, rails
High-carbon steel	0.50 – 1.10	Tools, springs, blades

Carbon content directly influences weldability: the higher the carbon, the greater the risk of cold cracking. To assess this risk, the carbon equivalent (CE) is used, calculated according to the IIW (International Institute of Welding) formula:

CE = C + (Mn/6) + [(Cr + Mo + V)/5] + [(Ni + Cu)/15]

A CE greater than 0.45% indicates a steel that is difficult to weld without preheating. For example, for an ASTM A36 steel with C = 0.25% and Mn = 1.0%: CE = 0.25 + (1.0/6) = 0.25 + 0.167 = 0.417%. This material is weldable without preheating, but with caution.

Low-Alloy Steels

Low-alloy steels contain total alloying elements between 1% and 5% by weight. Common elements include chromium, nickel, molybdenum, and vanadium. These steels offer better mechanical strength and hardenability than carbon steels. CSA G40.20/G40.21 standards cover high-strength low-alloy (HSLA) structural steels used in Canada.

Stainless Steels

Stainless steels contain at least 10.5% chromium, which forms a protective passive layer of chromium oxide. Four main families are distinguished:

Family	Structure	Characteristics	Applications
Austenitic (300)	FCC	Non-magnetic, excellent corrosion resistance, weldable	Food processing, chemical equipment
Ferritic (400)	BCC	Magnetic, moderate resistance, less expensive	Exhaust systems, decorative
Martensitic (400)	Hardened BCC	Hard, wear-resistant, weldable with precautions	Knives, turbines
Duplex (2205)	Mixed	High strength, excellent resistance to stress corrosion cracking	Offshore, petrochemical

The AISI/SAE designation uses three digits: the 200 and 300 series for austenitic grades (e.g., 304, 316), the 400 series for ferritic and martensitic grades (e.g., 430, 410). 316 contains molybdenum (2-3%) which improves pitting corrosion resistance.

Steel Designation Systems

CSA and ASTM Standards

In Canada, structural steels are designated according to CSA G40.20/G40.21 standards. Common grades include:

260W: minimum yield strength of 260 MPa

300W: minimum yield strength of 300 MPa

350W: minimum yield strength of 350 MPa (most common for structural framing)

400W: minimum yield strength of 400 MPa

The letter "W" indicates a weldable steel. ASTM (American Society for Testing and Materials) standards are also widely used: A36 (general structural steel), A572 (Grade 50, high strength), A514 (quenched and tempered steel, 690 MPa).

CSA Standards for Tubes and Pipes

CSA G40.20: general requirements for structural shapes and plates

CSA Z245.1: steel pipe for oil and gas transmission pipelines

ASTM A53: black and galvanized steel pipe, welded and seamless

ASTM A106: seamless pipe for high-temperature service

Material Marking and Identification

Each piece of steel must be identified by markings indicating the grade, heat number, and manufacturer. Marking methods include:

Tags: attached to bundles of sheet metal or structural shapes

Stamping: embossed marks on the piece

Paint: color code according to grade (varies by manufacturer)

Metal tags: attached by wire or welding

Golden rule: never cut or remove identification marks before transferring the information to the cut pieces. If in doubt about a material's identification, perform a spark test or use an XRF (X-ray fluorescence) analyzer if available.

Rapid Identification Tests

Spark Test

This test involves grinding the metal on a high-speed grinder and observing the sparks produced:

Material	Spark Characteristics
Mild steel	Long yellow sparks, few branches
High-carbon steel	Sparks with numerous white branches
Stainless steel	Short red sparks, no branches
Cast iron	Short red sparks, with pear-shaped branches

Magnet Test

A magnet distinguishes magnetic steels (ferritic, martensitic, carbon steels) from non-magnetic austenitic steels. Caution: work hardening can make some austenitic steels slightly magnetic.

Filings Test

The reaction of metal filings with acids or reagents can identify certain alloys. Copper sulfate test (CuSO₄ solution): a red copper deposit indicates the presence of iron; no reaction suggests stainless steel or a non-ferrous alloy.

Identification of Non-Ferrous Metals

Aluminum and Aluminum Alloys

Aluminum has a density of approximately 2.70 g/cm³ (one-third that of steel). Its corrosion resistance is due to a natural oxide layer. Aluminum alloys are designated by a four-digit system (AA – Aluminum Association standard):

Series	Principal Element	Characteristics
1xxx	Pure aluminum (99%)	Excellent conductivity, low strength
2xxx	Copper	High strength, poor weldability
5xxx	Magnesium	Good weldability, moderate strength
6xxx	Magnesium + Silicon	Extrudable, weldable, moderate strength
7xxx	Zinc	Very high strength, limited weldability

Alloys 6061-T6 and 6063-T5 are the most common in metal fabrication. The suffix "T6" indicates a solution heat treatment followed by artificial aging.

Copper and Copper Alloys

Pure copper (C11000) is used for its excellent electrical and thermal conductivity. The main alloys:

Brasses: copper-zinc (e.g., C26000, cartridge brass 70/30)

Bronzes: copper-tin (e.g., C51000, phosphor bronze)

Copper-nickels: copper-nickel (e.g., C70600, 90/10) for marine applications

Other Non-Ferrous Metals

Titanium: density 4.51 g/cm³, high strength, excellent corrosion resistance, used in aerospace and chemical industries

Nickel and alloys: Inconel, Monel, Hastelloy – resistance to high temperatures and aggressive corrosion

Zinc: used primarily for galvanizing steel

Lead: density 11.34 g/cm³, used for radiation shielding

Material Handling and Storage

Safe Handling Principles

Handling metals presents risks of serious injuries: cuts, crushing, back injuries, falls. Fundamental principles:

68.Load assessment: know the weight of pieces before lifting. For a steel plate: Weight (kg) = Length (m) × Width (m) × Thickness (mm) × 7.85. For example, a plate 2 m × 1 m × 10 mm weighs: 2 × 1 × 10 × 7.85 = 157 kg.

69.Lifting techniques: bend your knees, keep your back straight, carry the load close to your body.

70.Handling equipment: overhead cranes, hoists, forklifts, magnetic or mechanical lifting clamps.

71.Sling inspection: inspect synthetic and steel cable slings before each use. Never use a damaged sling.

Sling Lifting Rules

The sling angle affects the effective load on each leg:

Angle from Vertical	Load Factor per Leg
0°	1.00
30°	1.15
45°	1.41
60°	2.00

Caution: at 60° from vertical, each leg supports double the load. The maximum recommended angle is 60°; beyond this, the risk of failure increases considerably.

Material Storage

Plates and sheets: store flat on wooden or rubber supports to prevent contact corrosion. Separate different grades.

Structural shapes (beams, channels): store on sleepers spaced 1.5 to 2 m apart, with wedges to prevent tipping.

Tubes and pipes: store on racks with separators to prevent rolling.

Electrodes and welding wires: store in a dry location, at a temperature of 10 to 40 °C, with relative humidity below 60%. Low-hydrogen electrodes (E7018) must be kept in electrode ovens at 120-150 °C.

Aluminum and stainless steels: store separately from carbon steel to prevent contamination by iron particles (risk of pitting corrosion).

Identification of Material-Related Hazards

Galvanized steels: welding or grinding produces zinc oxide fumes that can cause "metal fume fever" (flu-like symptoms). Use adequate ventilation and appropriate respiratory protection.

Lead-painted steels: grinding or torch cutting releases toxic lead particles.

Stainless steels: welding produces hexavalent chromium (Cr⁶⁺), a carcinogen. Source extraction ventilation is mandatory.

Beryllium (in some copper alloys): extremely toxic by inhalation.

Surface Preparation Before Welding

Surface Cleaning

Weld quality depends directly on the cleanliness of the surfaces to be joined. Common contaminants are:

Contaminant	Source	Removal Method
Oil, grease	Lubricants, temporary protection	Degreasing with solvent, steam cleaner
Rust, mill scale	Atmospheric exposure, hot rolling	Wire brushing, grinding, chemical pickling
Paint	Marking, protection	Grinding, chemical stripping, abrasive blasting
Moisture	Condensation, outdoor storage	Drying, preheating
Aluminum oxide	Natural exposure	Stainless steel brushing, chemical pickling

Cleaning zone: at least 25 mm on each side of the weld, but 50 mm is recommended for critical applications.

Edge Preparation (Beveling)

Edge preparation geometries are defined by CSA W59 (steel) and CSA W47.1 (qualification) standards. Common types:

Type	Symbol	Description	Typical Thickness
Square edge (I)	I	No preparation, butt weld	≤ 3 mm
Single V	V	Bevel at 30-37.5° per side	6 – 20 mm
Double V	X	Bevel on both sides	> 20 mm
Single U	U	Rounded bevel	> 20 mm, limited access
Double U	UU	Rounded bevel on both sides	> 30 mm

The total bevel angle for a single V is generally 60° (30° on each side). The root face measures 1.5 to 3 mm depending on the application. The root gap (space between pieces) is 2 to 3 mm to allow complete penetration.

Cutting and Preparation Methods

Thermal Cutting (Oxy-fuel Cutting)

Oxy-fuel cutting is used for carbon steel (up to 300 mm thick). The principle: heat the steel to approximately 870-900 °C (ignition temperature), then direct a jet of oxygen that oxidizes the metal. The iron oxide (slag) is blown out of the cut.

Key parameters:

Oxygen pressure: 200-400 kPa (depending on thickness)

Fuel gas pressure (acetylene, propane, MAPP): 20-100 kPa

Cutting speed: 300-600 mm/min for 10 mm mild steel

Cut quality: a good cut shows regular vertical drag lines, a clean top edge without burrs, and a bottom edge without adherent slag.

Plasma Cutting

Plasma uses an electric arc to ionize a gas (air, argon, nitrogen) that reaches temperatures of 15,000 to 30,000 °C. It cuts all conductive metals, including aluminum and stainless steel. The heat-affected zone (HAZ) is smaller than with oxy-fuel cutting.

Waterjet Cutting

Abrasive waterjet cutting is heat-free (no HAZ), ideal for heat-sensitive materials. Used for aluminum, composites, and specialty steels.

Post-Cutting Cleaning

After thermal cutting, surfaces must be cleaned to remove:

Slag and burrs (grinding)

Mill scale (wire brushing)

Cutting oxide (light grinding)

For quality welds, the cut surface must be ground to achieve a smooth surface free of oxides.

Thermal Preparation Treatments

Preheating

Preheating is applied to:

119.Slow down the cooling of the weld and the HAZ

120.Allow hydrogen to diffuse out of the welded zone

121.Reduce thermal stresses

122.Prevent the formation of martensite in hardenable steels

The preheat temperature depends on the carbon equivalent, thickness, and ambient temperature. Typical values:

CE (%)	Thickness (mm)	Minimum Preheat
< 0.35	< 20	None (if T > 5 °C)
0.35 – 0.45	20 – 40	50 – 100 °C
0.45 – 0.60	> 40	100 – 150 °C
> 0.60	Any	150 – 250 °C

Preheat temperature verification is done with temperature-indicating crayons (calibrated melting temperature), thermocouples, or infrared pyrometers. The temperature must be measured at 75 mm from the weld joint.

Post-Weld Heat Treatment (PWHT)

PWHT (or stress relieving) is applied to:

Reduce residual stresses

Improve the HAZ microstructure

Restore ductility

Typical temperatures: 600-650 °C for carbon steels, with controlled heating and cooling rates (generally 200 °C/h maximum).

Applicable Canadian Standards

CSA W59 – Welded Steel Construction

This standard is the primary reference for structural steel welding in Canada. It covers:

Welding procedure qualification requirements (WPS/PQR)

Weld acceptance criteria

Dimensional tolerances

Inspection requirements

CSA W47.1 – Certification of Welding Companies

This standard requires welding companies to be certified according to their category (Division 1, 2, 3) based on the processes and materials used. The metal fabricator must verify that the company holds the appropriate certification for the work to be performed.

CSA G40.20/G40.21 – Structural Steels

This standard defines requirements for structural steel plates, shapes, and bars. It specifies mechanical properties, chemical composition, and dimensional tolerances.

CSA B149.1 – Natural Gas and Propane Installation Code

This standard applies to gas pipelines. For welding work on these pipelines, additional requirements apply concerning welder qualification and procedures.

Canadian Electrical Code, Part I, Chapter V

This code applies to work performed near electrical power lines. Rule 8-200 requires a minimum distance of 3 m between equipment and lines under 75 kV, and 5 m for lines over 75 kV. A request to de-energize or relocate the line must be made if these distances cannot be maintained.

Inspection and Quality Control Procedures

Dimensional Inspection

The metal fabricator must verify:

Piece dimensions (tolerances according to drawings and standards)

Squareness of assemblies (tolerance: ± 2 mm per meter)

Alignment of pieces before welding

Root gap and bevel angle

Interpass Temperature Control

The temperature between weld passes must not exceed the maximum temperature specified in the WPS (often 250 °C for carbon steels). Exceeding this limit can degrade mechanical properties.

Visual Inspection

Visual inspection is the first level of inspection. It verifies:

The presence of cracks, porosity, lack of fusion

Weld profile (reinforcement, toe angle)

Weld dimensions (width, height)

Summary

Metal identification relies on knowledge of designation systems (CSA, ASTM, AISI/SAE) and rapid tests (spark, magnet, filings).

The carbon equivalent (CE) is an essential tool for assessing weldability: CE = C + (Mn/6) + [(Cr + Mo + V)/5] + [(Ni + Cu)/15]. A CE > 0.45% requires preheating.

Austenitic stainless steels (300 series) are non-magnetic; ferritic and martensitic (400 series) are magnetic.

Safe handling requires knowing weights, inspecting slings, and respecting lifting angles (max 60°).

Surface preparation includes degreasing, pickling, and grinding over an area of at least 25 mm on each side of the joint.

Bevel geometries (I, V, X, U) are selected based on thickness and access.

Preheating is mandatory for high-CE steels, thick sections, and low ambient temperatures.

CSA W59, W47.1, and G40.20/G40.21 standards are the primary references in Canada.

The Canadian Electrical Code, Part I, Chapter V (Rule 8-200) requires minimum distances of 3 m (lines < 75 kV) and 5 m (lines > 75 kV) for work near power lines.

Common Pitfalls to Avoid

176.Confusing magnetic and non-magnetic stainless steels: austenitic grades (304, 316) are non-magnetic, but work hardening can make them slightly magnetic. Do not rely solely on the magnet test.

177.Forgetting the angle factor in slings: at 60° from vertical, each leg supports double the load. Always calculate the actual load on each leg.

178.Neglecting surface cleaning: welding on an oily or rusty surface will produce porosity and lack of fusion. Cleaning is not optional.

179.Using the wrong cutting process: oxy-fuel cutting does not work on aluminum or stainless steel (the oxide formed has a higher melting point than the base metal). Use plasma or waterjet.

180.Ignoring preheat temperature: welding high-CE steel without preheating causes cold cracks that may appear several hours after welding.

181.Confusing steel grades: 350W and 260W steel are not interchangeable. Verify markings before any cutting.

182.Removing identification marks: cutting off tags or stamps before transferring the information to cut pieces is a serious error.

183.Forgetting fume-related hazards: welding galvanized steel produces zinc oxide fumes (metal fume fever). Adequate ventilation is mandatory.

184.Not verifying company certification: according to CSA W47.1, only certified companies may weld load-bearing structures. Verify the division and scope of certification.

185.Welding near power lines without checking distances: Rule 8-200 of the Canadian Electrical Code, Part I, Chapter V requires minimum distances of 3 m and 5 m depending on voltage. Never approach equipment without authorization.

186.Confusing units of measurement: drawings may be in millimeters or inches. Systematically verify units before taking measurements.

187.Neglecting interpass temperature control: excessively high temperature between passes degrades the mechanical properties of the weld. Respect WPS limits.