120201c SMAW Fillet Welds on Mild Steel (Information Deck)

Question 1

Practical Welding Applications

Answer 1

Key Concepts:

• Welding involves various techniques; no single method is universally best.
• Personal development of unique welding techniques is important.
• Focus on the end result of the weld, rather than the specific technique used.

Guidance for Learners:
* Use proven procedures as a guide in developing your technique.
* Listen to instructors for basic, easily mastered techniques.

Welding Technique Considerations:
* Includes variables like electrode inclination, angle, arc length, bead type, and pass type.
* Evaluate techniques based on weld quality, speed, cost, stress/distortion, position effectiveness, and learning time.

Safety Reminder:
* Always prioritize safety for yourself and others.
* Review safety guidelines for equipment before starting.

Question 2

Cover Pass

Answer 2

Definition:
* A cover pass, also known as cap or wash coat, is a thin weave or series of passes.

Purpose:
* Applied as the final layer over a fill pass or passes in welding.
* Intended to eliminate undercut and enhance the weld’s appearance.

Characteristics:
* Provides a finish that is pleasing to the eye.
* Often built up slightly higher than the parent metal for reinforcement.

Question 3

Electrode Angle

Answer 3

Definition:
* The electrode angle is the position of the electrode relative to the angle of the parts being joined.

Standard Angles:
* Usually one half of the included joint angle.
* Perpendicular for butt joints, 45° for fillet welds.

Purpose and Application:
* Used to achieve the desired bead contour and direct weld metal placement.
* Utilizes arc force to prevent undercut and ensure good bead contour.

Adjusting for Undercut:
* Point heat towards undercut areas to correct issues, ensuring metal flows to the hottest point.

Considerations:
* Be mindful of gravity and electrode behavior.
* Adjust angle to compensate for sag and undercut.

Question 4

Electrode Inclination

Answer 4

Definition:
* Electrode inclination is the angle of the electrode relative to the workpiece and travel direction.

Types of Inclination:
* Forehand: Electrode points in the direction of travel.
* Backhand: Electrode points back at the puddle.

Inclination Angles:
* Measured in degrees from the perpendicular.
* Common range for SMAW: 5° to 30°, either forehand or backhand.

Impact on Welding:
* Inclination affects weld profile size, shape, and penetration depth.
* Forehand: Flatter, wider beads with less penetration, suitable for finishing and thin materials.
* Backhand: Deeper penetration and narrower beads, ideal for heavy beads.

Factors Influencing Inclination:
* Bead type, bead size, electrode type, and work position.

Question 5

Inclination for Flat Position

Answer 5

Recommended Inclination:
* Range from 5° forehand to 15° backhand.

Purpose:
* Achieves beads of acceptable shape and size for flat position welding.

Question 6

Inclination for Vertical Position

Answer 6

Uphand (Uphill) Welding:
* Specific inclination not detailed; adapt based on position and technique.

Downhand (Downhill) Welding:
* Requires more electrode inclination to control weld metal flow.

Question 7

Inclination for Overhead Position

Answer 7

Recommended Inclination:
* Same as flat position: 5° forehand to 15° backhand.

Purpose:
* Ensures effective welding in the overhead position.

Question 8

Inclination for Uphill Pipe Welding

Answer 8

Recommended Inclination:
* Square to the pipe surface or pointing to the pipe’s axis.

Variations:
* 5° backhand in the overhead position and 5° forehand in other positions.

Question 9

Fill Pass

Answer 9

• A second or filling bead in welding, sometimes called the hot pass.
• Used to fill, melt out slag, and undercut from the root bead.
• May require multiple passes for heavy welds.
• Can be stringer or weave beads.

Question 10

Finish Pass

Answer 10

• The final pass that finishes the surface, also known as the cap pass.
• It fills the groove and produces a finished surface, sometimes doubling as a fill pass in thinner materials.

Question 11

Fillet Weld

Answer 11

• A weld with a triangular cross-section, used to join parts typically at 90° to each other.

Question 12

Groove Weld

Answer 12

• A weld placed between two mating surfaces that usually lie in the same plane.

Question 13

Manipulative Welding Technique

Answer 13

• A technique involving a back and forth motion with cellulose-coated electrodes.
• Involves short arc length for penetration and metal deposit, and longer arc for more metal flow and blending.

Question 14

Polarity

Answer 14

• Refers to the pole of a DC power source to which an electrode or work lead is attached.
• Reverse polarity (DCEP) attaches to the positive pole, straight polarity (DCEN) to the negative.

Question 15

Plane

Answer 15

• A flat surface on which a straight line joining any two points would lie.

Question 16

Postheat Treatment

Answer 16

• Applied heat treatment of the weldment after the completion of welding.

Question 17

Preheat

Answer 17

• Heat applied to the weldment before starting any welding.

Question 18

Root Face

Answer 18

• Area of metal removed from the root edge to form a square face at the root of a butt joint.

Question 19

Root Pass

Answer 19

• The first or penetrating bead made at the root of the joint.

Question 20

Stringer Bead

Answer 20

• A single passweld performed with no side-to-side motion, involving only forward movement.
• Size depends on various factors like electrode size, current setting, and speed of travel.

Question 21

Stringer Padding

Answer 21

Method:
* Using stringer beads to build up a surface uniformly.

Application:
* Each bead partially overlaps the previous one, maintaining level crowns without valleys.

Cleaning:
* Advisable to deslag between passes, except in vertical positions where slag runs downward.

Question 22

Stringer Fill

Answer 22

Purpose:
* To blend into a finished contour using overlapping stringer beads.

Technique:
* Start at the bottom of the joint, with each pass applied over the previous one.

Considerations:
* Adjust current settings, bead size, electrode angle, and arc length for optimal results.

Question 23

Tack Weld

Answer 23

Definition:
* A short weld used to hold parts together and in alignment until final welding.

Usage:
* Ensures stability and alignment during the welding process.

Question 24

Weave Bead

Answer 24

Description:
* A bead made with side-to-side motion in addition to the forward travel.

Characteristics:
* Leads to higher localized heat and slower cooling in the weld zone.

Guidelines:
* Width based on electrode size and current setting, with side motion ideally 2-3 times the electrode diameter.

Question 25

**Weave Padding**

Answer 25

**Technique:** * Utilizes weave beads to build up wear surfaces. **Application:** * Beads are placed to blend smoothly with previous ones, creating an even, solid layer of weld metal.

Question 26

**Herringbone Weave**

Answer 26

**Description:** * Cross the center with a longer arc and faster travel, depositing little metal. Pause at edges after shortening the arc for blending. **Application:** * Eliminates undercut at weld toes, covers craters of previous passes. **Versatility:** * Suitable for flat, vertical, and overhead positions, and as a fill, fill and finish, or cover pass.

Question 27

**Crescent Weave**

Answer 27

**Characteristics:** * Small forward progression compared to side movement. Adjust forward progression for lighter or heavier beads. **Suitability:** * Usable for all positions, but watch for undercut in vertical and overhead positions. **Use:** * Ideal for fill or fill and finish passes.

Question 28

**Lazy L Weave**

Answer 28

**Technique:** * Diagonal weave resembling an 'L', overlapping with previous passes. **Application:** * Used as a cover pass over stringer fill passes, mainly in horizontal position. **Considerations:** * Requires skill for successful application, may not be allowed in all welding procedures.

Question 29

**Sawtooth Weave**

Answer 29

**Description:** * A variation of stringer bead with side motion limited to half the electrode's diameter. **Purpose:** * Prevents undercutting on cap layers of multi-pass welds or root beads in open gap horizontal welds. **Application:** * Acts as a gravitational correction, especially along the top edge of the weld.

Question 30

**Weld Procedure Specifications (WPS)**

Answer 30

**Definition:** * A detailed document specifying the necessary variables for a specific welding application to ensure consistent quality by trained welders. **Purpose:** * Ensures repeatability and quality of welds; includes variables proven through destructive tests. **Key Variables in WPS:** 1. **Project Identification:** No thickness limit for SMAW process joints. 1. **Material Selection:** Match filler metal to base material properties. 1. **Weld Position:** Determine the placement of the weld. 1. **Process Selection:** Choose the appropriate welding process. 1. **Material Preparation:** Varies based on material thickness and welding side. 1. **Weld Size:** Calculate for load capacity, considering contour and leg length. 1. **Pass Sequence:** Plan for fusion and penetration, avoiding slag traps. 1. **Technique:** Stringer beads, weave beads, or combinations. 1. **Procedure Parameters:** Current, polarity, electrode type, and size for joint type and position.

Question 31

**Setting the Current and Polarity**

Answer 31

**Initial Steps:** * Select the correct polarity for the electrode. * Adjust the machine to the recommended current setting for the chosen electrode. **Amperage Adjustment:** * Start with a range provided by manufacturers or use general rules: * **Imperial:** Electrode diameter in thousandths of an inch as the amperage. (e.g., 1/8" = 0.125" = 125 amps) * **Metric:** Multiply electrode diameter by 40. (e.g., 3.2 mm × 40 = 128 amps) **Fine-Tuning:** * These are starting points. Fine-tune the current based on arc characteristics and puddle reactions. * Test on scrap metal similar in thickness to the weld piece. * Adjust for a stable arc, minimal spatter, and a smooth bead with the correct profile.

Question 32

**Polarity Check**

Answer 32

**Context:** * Essential for setting the right polarity in DC welding. **Polarity Switching:** * Some machines have a control panel switch, others require manual cable switching. **Quick Polarity Check Procedure:** 1. Use a cellulose type electrode (e.g., E4310 / E6010). 2. Weld a bead on scrap material at normal settings, observe the puddle and listen to the arc. 3. Switch cables and repeat. Compare puddle reactions and arc sounds: * **Electrode Positive (EP):** Normal puddle reactions with a smooth, crisp sound, like bacon frying. * **Electrode Negative (EN):** More violent puddle reactions, longer arc, higher fume emission, and a hissing sound, like rushing air.

Question 33

**Body Position in Welding**

Answer 33

**Importance of Comfort and Visibility:** * Find a position that is comfortable while ensuring clear visibility of the weld puddle. **Using the Booth Anchor Post:** * Use the booth anchor post for support. It helps you stay steady and relaxed while welding. **Movement and Support:** * Your body should be able to move freely yet remain supported by the anchor post. **Direction of Welding:** * Typically weld across your body. * For right-handed people, from left to right; reverse for left-handed individuals.

Question 34

**Tapping Method for Starting an Arc**

Answer 34

**Procedure:** * Hold the electrode perpendicular to the work surface. * Strike the arc by tapping the electrode's end near the welding point, then quickly withdraw to establish the arc. **Key Points:** * Immediate withdrawal after contact prevents electrode fusion to the metal. * Be cautious not to raise the electrode too far, or the arc will break. **Caution:** * Avoid stray arc strikes outside the weld zone to prevent metal brittleness and cracks.

Question 35

**Scratch Method for Starting an Arc**

Answer 35

**Procedure:** * Use a motion similar to striking a match. * Strike the arc by scratching the electrode across the surface, then quickly withdraw to the desired arc length. **Key Points:** * Ensure smooth and controlled scratching to start the arc effectively. **Caution:** * Stray arc strikes outside the weld area are serious faults, as they can weaken the metal. * Avoid striking the arc outside the designated weld zone.

Question 36

**Stops and Restarts in SMAW Welding**

Answer 36

**Context:** * Necessary when changing electrodes or pausing the welding process. **Crater Management:** * Stopping leaves a deep crater; ensure uniformity when restarting to avoid weld faults. **Preparation for Restart:** * Clean the original bead and crater area with a chipping hammer and wire brush to remove slag. **Restart Procedure:** * Start the arc within the weld zone but not in the original crater. * Move the arc backward into the crater to blend the new weld pool with the previous crater's edge. * Continue forward to complete the weld. **Key Point:** * Ensure the restart integrates seamlessly with the previous weld to maintain uniformity and strength.

Question 37

**Arc Length in Welding**

Answer 37

**General Rule:** * Normal arc length is typically the same as the electrode core wire diameter. (e.g., 3.2 mm electrode = 3.2 mm arc length). **Influence on Weld Bead:** * Arc length affects penetration, deposition rate, weld height and width, and finished appearance. **Types of Arc Length:** **Short Arc (Choked Arc):** * Deeper penetration, higher deposition rate, narrower puddle with build-up. **Long Arc:** * Shallow penetration, lower deposition rate, wider puddle with good edge blending. **Normal Arc:** * Balances characteristics of short and long arcs for versatile application.

Question 38

**Crucible Cup Effect in Welding**

Answer 38

**Definition:** * The cup-like shape formed by the flux coating at the end of some electrodes. **Impact on Arc Length:** * Heavier flux coatings create deeper cups, allowing the electrode to be held closer to the metal. **Examples:** * E4914 (E7014) electrodes have greater cupping than * E4310 (E6010) and should be held as if touching the metal. * E4924 (E7024) electrodes, with heavy flux coating, are designed for the drag technique, maintaining normal arc length by contacting the metal surface. **Significance:** * Electrodes with high iron powder coatings, or "contact electrodes," use this effect for effective welding.