POLYTECHNIC SERIES SHIELD METAL ARC WELDING (SMAW) FOR BEGINNER 1 ST EDITION 2023 ABDUL RAHMAN MAT ABU IZAN FAHMEE NORDIN
SHIELD METAL ARC WELDING (SMAW) FOR BEGINNER 1 ST EDITION 2023 ABDUL RAHMAN MAT ABU IZAN FAHMEE NORDIN POLYTECHNIC SERIES
Copyright All rights reserved. No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of Politeknik Mukah. Authors: ABDUL RAHMAN MAT ABU IZAN FAHMEE NORDIN Publisher: Politeknik Mukah KM 7.5, Jalan Oya 96400 Mukah Sarawak Malaysia www.pmu.edu.my
4 SYNOPSIS This practical workbook is compiled to provide guidance and facilitate practical work so that students can equip themselves with the knowledge and skills needed in the field of arc welding (SMAW). It also aims to ensure that students can do work more systematically and planned. The compilation of this practical workbook is done according to the basic skill level in arc welding so that students can practice in improving the required skill level. The practical work done by students can be put into practice in producing quality products. Hopefully with the result of this practical workbook it can help and be a reference for students in getting more skills and knowledge when doing practical work in the welding workshop.
5 ABOUT THE AUTHOR ABDUL RAHMAN B MAT ABU received a Bachelor Of Mechanical Engineering with Honors from Universiti Teknologi Malaysia (UTM) in 2016 and Diploma In Mechanical Engineering with Education from Universiti Teknologi Tun Hussein Onn (UTHM) in 2002. Lecturer of Mechanical Engineering in Politeknik Mukah, Sarawak. He has taught in Mechanical Engineering subject for almost 20 years. IZAN FAHMEE BINTI NORDIN received a Bachelor Of International Business Management with Honors from Universiti Utara Malaysia (UUM) in 2006 and Diploma In Business Studies from Kolej Yayasan Pelajaran Mara Kuantan (KYPM) in 2002. Lecturer of Commerce Department, Politeknik Mukah, Sarawak.
INTRODUCTION TO WELDING AND SMAW 7 01 SAFETY PRECAUTION DURING WELDING 8 02 03 SMAW TOOLS & EQUIPMENTS 9 SMAW PROCEDURE , SOP & TERMINOLOGY 10-27 04 DISSCUSION ON WELDING RESULTS AND 05 WELDING DEFECT 28-32 TABLE OF CONTENTS 6
7 OBJECTIVE This eBook is structured to guide and facilitate practical work so that students can equip themselves with the knowledge and skills needed in the field of weldings. It also aims to ensure that students can do their work more systematically and organized.The preparation of this practical workbook is carried out according to the level of basic skills in arc welding so that the student can do training in improving the required level of skills. The practical work done by the students is expected to be practiced in producing quality products. Hopefully this eBook can help and be a reference to students in gaining more skills and knowledge when doing practical work in the welding workshop.
SHIELD METAL ARC WELDING (SMAW) FOR BEGINNER After finished this topic you will have knowledge to ; 1. Practice safety in workshop among yourself and others. 2. How to set up and use SMAW machine including right tools selection. 3. Make and keep WELDING by following standard SOP. 4. Make use of the AWS in electrode classification system. 1
1.0 INTRODUCTION Welding is a process of connecting two or more materials using the method of forcepower attraction of solid atoms and uniting the atoms in a fixed state .Arc welding is one method of breaking two pieces of metal into pieces. The edges of the two basic metals are heated with the heat of the arc that exists between the ends of the electrodes of the metal’s surface, to high temperatures (1500°C) so that they can melt the united metals. This arc welding process is also known as the melting welding method. The base metal is normally melted first, followed by the addition of a filler material to create a pool of molten metal (the weld pool), which cools to form a joint that , depending on the weld design (butt, full penetration, fillet, etc.), may be stronger than the base metal. To create a weld, pressure can either be applied alone, in combination with heat, or both. 9
2.0 SAFETY PRECAUTION DURING WELDING 1. Gases and fumes can be hazardous. 2. Keep your head away from the vapours or gases. 3. Use adequate ventilation, arc exhaust, or both to keep fumes and gases out of the general area and your breathing zone. 4. The SMAW procedure can tolerate wind and exhaust from ventilation equipment. 5. Avoid touching the electrode or the metal components of the electrode holder. 6. Protect your body with dry insulation between it and the metal being welded or ground. 7. Arc Rays can harm skin and eyes. 10
3.0 SMAW TOOLS & EQUIPMENT 11 PPE 1.Apron 2.Gloves 3.Welding helmet 4.Safety shoes SMAW TOOLS 1.Player 2.Chipping hammer 3.Wire brush 4.Jig magnet It is the responsibility of each student to always demonstrate an attitude of desire to maintain safety and discipline while conducting the exercises in the workshop. It is his duty to control and protect himself and others from exposure to dangerous objects. In addition, it should always be diligent and careful in using arc welding equipment. Students also need to know and apply safety rules while working. It should also use eye protection, face protection, suitable workshop clothes and other suitable safety equipment to maintain safety.
4.0 SHIELDED METAL ARC WELDING -SMAW Shielded metal arc welding (SMAW), also known as manual metal arc welding (MMAW) or stick welding, is one of the most commonly used arc welding techniques. The consumable electrode rod, which is formed of filler material (often steel) and is covered with a flux, is used to create an arc between the base material and the base material in order to protect the weld region from oxidation and contamination by releasing carbon dioxide (CO2) gas during the welding process. A separate filler is not required because the electrode core itself serves as the filler material. 12
4.1 SMAW PROCESS ❖ During welding process it will creates a joint or connection between two pieces of base metal. ❖ Material as the molten weld puddle hardens . ❖ When done correctly, it produces a bead on steel that is more durable than the nearby base metal. ❖ Weld puddles are formed by the core rod, flux coating, and work components when they heat up and melt together . ❖ A welder monitors and controls the weld puddle while welding. 13 BASE METAL Fig 4.1.1 Running bead on mild steel(base metal) RUNNING BEAD
4.2 SMAW TERMINOLOGY PROCESS 14
4.3 SHIELDING GAS The flux coating melts, forming a shielding gas . This shielding gas shields the weld puddle from the air to prevent contamination while it is still molten. 15 The shielding gas stabilize the arc while shielding the molten puddle from the atmosphere.
4.4 SLAG ❖ Slag is made up of the flux coating and base metal impurities that float to the weld's surface . ❖ Slag forms a sturdy covering by immediately solidifying . ❖ Additionally, the slag inhibits the weld's rate of cooling . ❖ When the slag is hard, it can be chipped away and cleaned using a wire brush. 16 Fig 4.4.1 Welder chips the slag off of a base metal during the welding Fig 4.4.2 Slag formation above the running bead SLAG BEAD
4.5 SMAW WELDING MACHINE WORK PROCESS SMAW welding machines use operational principles electric circuit that sustains a welding arc is used in the SMAW process to turn fuel or electric line electricity into heat. The welding arc generates strong, highly concentrated heat. The end of the electrode and a section of the workpiece start to melt right away. 17 A straight AC machine will not have a polarity switch like this AC/DC machine Fig 4.5.1 Schematic diagram for SMAW machine
4.6 SMAW WELDING MACHINE There are five types of arc welding machines. ✓ Rectifier (DC) ✓ Changes (AC) ✓ AC/DC combination ✓ Engine- (petrol or diesel) ✓ Electric motor-(transformer) 18 Fig4.6.1. SMAW MACHINE DC 3 PHASE (400AMP) by Cruxweld Industrial Equipments (P) Ltd
4.7 SMAW MACHINE AND TOOLS ❖ The electrode cable, electrode, electrode holder, electrode, and arc are all parts where current travels . The current passes through the base material, to the work clamp, and back to the welding machine on the work side of the arc. 19 Fig 4.7.1 SMAW machine tools and setting MACHINE START UP
4.8 SMAW START AND MACHINE SETUP 20 Settings on the machine – Polarity : AC, DC+, DC- – Amperage Output Operator Controlled Variables – Work Angle – Travel Angle – Arc Length – Travel Speed
4.9 WORK ANGLE & TRAVEL ANGLE 21 Additionally known as Lead Angle .The angle formed by the electrode and the plane perpendicular to the weld axis is known as the journey (lead) angle (20° to 30° ) The angle between the electrode and the work, as shown on the left, is known as the work angle (90° ). Depending on the position in which the weld is being formed,work angles can be change.
4.10 WELDING ELECTRODE ❖ Welding electrodes are metal wires with baked on chemical coatings. The rod is used to sustain the welding arc and to provide the filler metal required for the joint to be welded. The coating protects the metal from damage, stabilizes the arc, and improves the weld. 22 ❖ When the electrode makes contact with the workpiece and completes the circuit an arc forms, similar to turning on a light. The space between the electrode's tip and the work is where the electric arc forms 10,000°F is reached by the arc melting the electrode and base material.
4.11 ELECTRODE SPECIFICATIONS ❖ Consumable ▪ it gets melted during the welding process by composed of two parts ❖ Core Rod (Metal Filler) ▪ Carries welding current ▪ Becomes part of the weld ❖ Flux Coating ▪ Produces a shielding gas ▪ Can provide additional filler ▪ Forms a slag A.Mild Steel B.High Carbon Steel C.Hard Surfacing D.Alloys – special purpose Fig 4.11.1 Weld puddles form by electrode
4.12 ELECTRODE COATING 24 • To Produce Shielding Gases • To Produce a Slag Covering • To Provide Mechanical and Physical Properties • To Increase Deposit Rates
4.13 AWS CLASSIFICATION FOR SMAW ELECTRODE 25 E6013 ELECTRODE TENSILE IN PSI POSITION TYPE OF COATING 60 X 1000=60000 PSI HIGH CELLULOSE SODIUM 1-ALL POSITIONS FLAT,HORIZONTAL, VERTICAL AND OVERHEAD 2.-HORIZONTAL AND FLAT 3.-FLAT ONLY *PENETRATION MILD AND FOR GENERAL PURPOSE
4.14 ELECTRODE CHARACTERISTICS 26 AWS Current Class Covering Requirements Position Characteristics EXX 10 Cellulose DCEP All Deep Penetration, Sodium With Ripples EXX 11 Cellulose AC, DCEP All Deep Penetration, Potassium Flat Decking With Ripples EXX22 Rutile DCEN, AC Flat, Horiz. Fillet Deep Penetration, Sodium With Ripples EXX 24 Rutile AC, DCEP, DCEN Flat, Horiz. Fillet High Deposition 50% Iron Shallow Penetration Powder EXX 27 Mineral AC,DCEP, DCEN Flat, Horiz. Fillet High Deposition 50% Iron Shallow Penetration Powder AWS Current Class Covering Requirements Position Characteristics EXX 12 Rutile DCEN, AC All Mild to Medium Penetration Sodium EXX 13 Rutile AC, DCEP, DCEN All Mild Penetration Sodium EXX 14 Rutile AC, DCEN All Medium Penetration 30% Iron Powder EXX 18 Low-Hydrogen DCEP, AC All Medium Penetration 30% Iron Powder EXX 28 Low-Hydrogen AC, DCEP Flat, Horiz. Fillet High Deposition 50% Iron Powder *Always used for general works and easy to handle
4.15 ELECTRODE OVEN 27 Stick welding (SMAW) activities require the use of welding rod ovens, also known as electrode holding ovens or electrode stabilization ovens. They prevent moisture from the surroundings from absorbing into the welding rods and electrodes. Fig.4.15.1 Bench type electrode oven Fig .4.15.2 Portable type @quiver
4.16 SMAW ARC START Two (2 )method to start arc in SMAW process. One of the following methods can be used for this: 1. Scratch start: Use a match to scratch the electrode against the base metal. 2. Tap the rod against the base metal to begin. 28 1 2
4.17 BASIC SMAW JOINT 29 BASIC JOINT 1. Butt Joint 2. Lap Joint 3. Tee Joint 4. Corner Joint 5. Edge Joint
5.0 DISCUSSION -WELDING DEFECT ON BASE METAL 30 Welding defects can be defined as weld surface irregularities, discontinuities, imperfections, or inconsistencies that occur in welding parts. Types of Welding Defects •Slag Inclusions. •Porosity. •Undercut. •Weld Crack. •Incomplete Fusion. •Incomplete Penetration. •Spatter. FIG 5.0.1 FRONT VIEW TYPE OF SMAW DEFECT ON BASE METAL
5.1 WELDING DEFECT ON BASE METAL 31 Reason for Poor Welds ❑ Machine adjustment too hot or too cold ❑ Electrode size too large or too small ❑ Improper movement of electrode ❑ Improper angle of holding electrode ❑ Improper base metal preparation ❑ Arc length too long or too short
5.2 SMAW ADVANTAGES & DISADVANTAGES SMAW ADVANTAGES 1. Cost-effective portable 2. Simple to use outside 3. Every positional capability 4. Simple to switch between a variety of base materials SMAW DISADVANTAGES 1. Reduced consumable effectiveness 2. Very thin materials are challenging to fuse repeated and weld 3. Restarts decreased operating factor 4. SMAW requires more operator skill than some other procedures do. 32
A. APPLICATION ACTIVITIES-SMAW PROJECT DESIGN 33
B. APPLICATION ACTIVITIES-ACTUAL SMAW PROJECT 34 BUTT JOINT RUNNING BEAD CORNER JOINT 90 ° CLOSED EDGE BASE METAL-MILD STEEL THICKNESS-5 MM
35 Cary, Howard B.; Helzer, Scott C. (2005), Modern Welding Technology, Upper Saddle River, New Jersey: Pearson Education, ISBN 978-0-13-113029-6 Jeffus, Larry (1999), Welding: Principles and Applications (4th ed.), Albany, New York: Thomson Delmar, ISBN 978-0-8273-8240-4 Lincoln Electric (1994), The Procedure Handbook of Arc Welding, Cleveland, Ohio: Lincoln Electric, ISBN 978-99949-25-82-7 Miller Electric Mfg Co (2013). Guidelines For Shielded Metal Arc Welding (SMAW) (PDF). Appleton, Wisconsin: Miller Electric Mfg Co. Archived from the original (PDF) on 2015-12-08. Weman, Klas (2003), Welding processes handbook, New York: CRC Press, ISBN 978-0-8493-1773-6 REFERENCES
36 THANK YOU