Wednesday, 3 September 2008
A Basic Guide Of ARC Welding Electrods
INTRODUCTION
ELECTRODE IDENTIFICATION
The electrode is 1/8" in diameter
The "E" stands for arc welding electrode.
Next will be either a 4 or 5 digit number stamped on the electrode. The first two numbers of a 4 digit number and the first 3 digits of a 5 digit number indicate the minimum tensile strength (in thousands of pounds per square inch) of the weld that the rod will produce, stress relieved. Examples would be as follows:
E60xx would have a tensile strength of 60,000 psi E110XX would be 110,000 psi
The next to last digit indicates the position the electrode can be used in.
- EXX1X is for use in all positions
- EXX2X is for use in flat and horizontal positions
- EXX3X is for flat welding
The last two digits together, indicate the type of coating on the electrode and the welding current the electrode can be used with. Such as DC straight, (DC -) DC reverse (DC+) or A.C.
I won't describe the type of coatings of the various electrodes, but will give examples of the type current each will work with.
ELECTRODES AND CURRENTS USED
- EXX10 DC+ (DC reverse or DCRP) electrode positive.
- EXX11 AC or DC- (DC straight or DCSP) electrode negative.
- EXX12 AC or DC-
- EXX13 AC, DC- or DC+
- EXX14 AC, DC- or DC+
- EXX15 DC+
- EXX16 AC or DC+
- EXX18 AC, DC- or DC+
- EXX20 AC ,DC- or DC+
- EXX24 AC, DC- or DC+
- EXX27 AC, DC- or DC+
- EXX28 AC or DC+
CURRENT TYPES
Ac current changes it's polarity 120 times a second by it's self and can not be changed as can DC current.
ELECTRODE SIZE AND AMPS USED
| Electrode Table | ||
| 1/16" | 20 - 40 | UP TO 3/16" |
| 3/32" | 40 - 125 | UP TO 1/4" |
| 1/8 | 75 - 185 | OVER 1/8" |
| 5/32" | 105 - 250 | OVER 1/4" |
| 3/16" | 140 - 305 | OVER 3/8" |
| 1/4" | 210 - 430 | OVER 3/8" |
| 5/16" | 275 - 450 | OVER 1/2" |
Note! The thicker the material to be welded, the higher the current needed and the larger the electrode needed.
SOME ELECTRODE TYPES
E6010 This electrode is used for all position welding using DCRP. It produces a deep penetrating weld and works well on dirty,rusted, or painted metals
E6011 This electrode has the same characteristics of the E6010, but can be used with AC and DC currents.
E6013 This electrode can be used with AC and DC currents. It produces a medium penetrating weld with a superior weld bead appearance.
E7018 This electrode is known as a low hydrogen electrode and can be used with AC or DC. The coating on the electrode has a low moisture content that reduces the introduction of hydrogen into the weld. The electrode can produce welds of x-ray quality with medium penetration. (Note, this electrode must be kept dry. If it gets wet, it must be dried in a rod oven before use.)
It is hoped that this basic information will help the new or home shop welder identify the various types of electrodes and select the correct one for their welding projects.
Sunday, 31 August 2008
Piping
Industrial process piping (and accompanying in-line components) can be manufactured from wood, glass, steel, aluminum, plastic, copper, and concrete. The in-line components, known as fittings, valves, and other devices, typically sense and control the pressure, flow rate and temperature of the transmitted fluid, and usually are included in the field of piping design. Piping systems are documented in Piping and Instrumentation Diagrams. If necessary, pipes can be cleaned by the tube cleaning process.
Plumbing is a piping system that most people are familiar with, as it constitutes the form of fluid transportation that is used to provide potable water and fuels to their homes and business. Plumbing pipes also remove waste in the form of sewage, and allow venting of sewage gases to the outdoors. Fire sprinkler systems also use piping, and may transport potable or nonpotable water, or other fire-suppression fluids.
Piping also has many other industrial applications, which are crucial for moving raw and semi-processed fluids for refining into more useful products. Some of the more exotic materials of construction are titanium, chrome-moly and various other steel alloys.
American Society of Mechanical Engineers (ASME)
The American Society of Mechanical Engineers (ASME) is a professional body, specifically an engineering society, focused on mechanical engineering. The ASME was founded in 1880 by Alexander Lyman Holley, Henry Rossiter Worthington, John Edison Sweet and Matthias N. Forney in response to numerous steam boiler pressure vessel failures. The organization is known for setting codes and standards for mechanical devices. The ASME conducts one of the world's largest technical publishing operations through its ASME Press, holds numerous technical conferences and hundreds of professional development courses each year, and sponsors numerous outreach and educational programs.
The organization's stated vision is to be the premier organization for promoting the art, science and practice of mechanical and multidisciplinary engineering and allied sciences to the diverse communities throughout the world. Its stated mission is to promote and enhance the technical competency and professional well-being of its members, and through quality programs and activities in mechanical engineering, better enable its practitioners to contribute to the well-being of humankind. As of 2006, the ASME has 120,000 members.
Core values include:
- Embrace integrity and ethical conduct
- Embrace diversity and respect the dignity and culture of all people
- Nurture and treasure the environment and our natural and man-made resources
- Facilitate the development, dissemination and application of engineering knowledge
- Promote the benefits of continuing education and of engineering education
- Respect and document engineering history while continually embracing change
- Promote the technical and societal contribution of engineers
ASME Codes and Standards
ASME is one of the oldest and most respected standards-developing organizations in the world. It produces approximately 600 codes and standards, covering many technical areas, such as boiler components, elevators, measurement of fluid flow in closed conduits, cranes, hand tools, fasteners, and machine tools.
Note that:
- A Standard can be defined as a set of technical definitions and guidelines that function as instructions for designers, manufacturers, operators, or users of equipment.
- A standard becomes a Code when it has been adopted by one or more governmental bodies and is enforceable by law, or when it has been incorporated into a business contract.
The ASME Boiler and Pressure Vessel Code (BPVC)
The largest ASME standard, both in size and in the number of volunteers involved in its preparation, is the ASME Boiler and Pressure Vessel Code (BPVC). BPVC is a standard that provides rules for the design, fabrication, and inspection of boilers and pressure vessels. It is reviewed every three years. The BPVC consists of twelve volumes as follows:
- I - Power Boilers
- II - Materials
- Part A - Ferrous Materials Specifications
- Part B - Nonferrous Material Specifications
- Part C - Specifications for Welding Rods, Electrodes and Filler Metals
- Part D - Properties (Customary units)
- Part D - Properties (Metric units)
- III - Rules for Construction of Nuclear Facility Components
- Division 1, Subsection NCA - General Reqs for Divisions 1, 2, and 3
- Division 1, Subdivision NB - Class 1 Components
- Division 1, Subdivision NC - Class 2 Components
- Division 1, Subdivision ND - Class 3 Components
- Division 1, Subdivision NE - Class MC Components
- Division 1, Subdivision NF - Component Supports
- Division 1, Subdivision NG - Core Support Structures
- Division 1, Subdivision NH - Class 1 Components in Elevated Temp Service
- Division 1, Appendices
- Division 2, Code for Concrete Reactor Vessels and Containment
- Division 3, Containment Systems & Transportation Packaging of Spent Nuclear Fuel
- IV - Heating Boilers
- V - Nondestructive Examination
- VI - Recommended Rules for the Care and Operation of Heating Boilers
- VII - Recommended Guidelines for the Care of Power Boilers
- VIII - Pressure Vessels
- Division 1 - Design and construction code for pressure vessels up to 3000 psig pressure, and having design factor 3.5 on tensile and other yield and temperature considerations.
- Division 2 - Alternative Rules
- Division 3 - Alternative Rules for Construction of High Pressure Vessels
- IX - Welding and Brazing Qualifications
- X - Fiber-Reinforced Plastic Pressure Vessels
- XI - Rules for In-service Inspection of Nuclear Power Plant Components
- XII - Rules for Construction and Continued Service of Transport Tanks
The ASME Pressure Piping Code (B31)
- B31.1 - Power Piping
- B31.3 - Process Piping
- B31.4 - Pipeline Transportation Systems for Liquid Hydrocarbons and Other Liquids
- B31.5 - Refrigeration Piping
- B31.8 - Gas Transportation and Distribution Piping
- B31.9 - Building Services Piping
- B31.11 - Slurry Transportation Piping Systems
Notable members
- Abdul Rahman Al-Athel
- Nancy D. Fitzroy.[1]
- Alexander C. Monteith
- Hugh Pembroke Vowles
- Adam Gent
ASME Student Professional Development Conference (SPDC)
The Student Professional Development Conference or SPDC is a conference that is run and maintained by ASME. The purpose for the conference is to allow students to network with other students from different colleges and engineers that are out in the work field, host competitive student contests, and gives them the opportunity to see what ASME can do for them professionally. Conferences are held in ten different districts with each district representing a certain section. Districts A-F are held in North America, District G is in Asia and Australia, District H includes most of Europe, District I is in Central and South America, and District J covers the MIddle East and parts of Africa. The location for each district changes every year and colleges attend the conference that is closest to them.[2]
ASME Student Competitions
Without a doubt, students attend the conference for the competitions. There are four competitions held at each conference and they are:
- Old Guard Oral Presentation Competition
- Old Guard Technical Poster Competition
- Technical Web Page Competition
- Student Design Competition
Each competition has its own set of rules and prizes. The most prestigious out of the four is the Student Design Competition as it allows engineering students to showcase their abilities, engineering knowledge, and creativity. Every year a problem statement is put up on the ASME SDC website which states the problem that must be solved and the various constraints that go along with it. The first place team at each district are then invited to compete in an international competition held at ASME's International Mechanical Engineering Congress and Exposition (IMECE).
American Welding Society (AWS)
The American Welding Society (AWS) is a nonprofit organization dedicated to advancing the science, technology, and application of welding and allied joining and cutting processes, including brazing, soldering, and thermal spraying. The organization is headquartered in Miami, Florida, but also conducts events and individual section and district meetings throughout the United States and in international locations. The organization is perhaps best known for its code and certification procedures, which provide industry standards for the welding and joining of metals, plastics and other materials. Through their publications, internet forums, member services, local and national events, educational resources, networking activities, and certification procedures, AWS keeps welding professionals and those interested in materials science up to date with the most current advances and procedures in the industry. As of September 2006, the society contains about 50,000 members, most within the United States.
History of the American Welding Society
The roots of the American Welding Society stretch back to World War I, when the sudden demands of swiftly producing military equipment brought the welding industry into focus. President Woodrow Wilson created a Welding Committee of the Emergency Fleet Corporation, which worked with the already existing National Welding Council. By 1919, industry leaders agreed that dependable and objective information on welding was crucial for further U.S. industrial development, and the two organizations merged together to create the American Welding Society.
An immediate need was to create a publication that could objectively cover the scientific advances of the industry, and in 1922, AWS started publishing the Welding Journal. The Welding Journal now appears monthly, and contains peer-reviewed articles on welding and materials science along with industry news and information about society events and members.
AWS also became concerned about welding and safety standards, and began offering certification standards and safety procedures to offer guidance on secure welding techniques and safety procedures. Today, AWS publishes more than 100 codes and procedures detailing welding standards for multiple metals, composite materials, and plastics.
AWS Codes and Specifications
AWS publishes codes on multiple aspects of welding and materials joining. The code books are assigned specific letters and numbers for easy reference, and many welders will refer to a specific code letter/number combination when referring to the code book. Different welding methodologies, inspection methods, and metals are published under different codes. For example, AWS B1.11 explains how to visually examine welds; AWS B2.1-1-004 explains welding carbon steel of thickness range of 18 through 10 gauge with semiautomatic metal gas arc welding; and AWS C2.20/C2.20M explains metalized zinc cathodic protection systems. Some codes also describe the standards used by AWS to certify welders, inspectors, and welding educators. All codes are available in hard copy, and in recent years AWS has started to make most codes available online.
AWS Certification
AWS certifies welders, inspectors, engineers, fabricators, radiographic interpreters, and robotic arc welders. Certification consists of detailed testing procedures. The Radiographic Interpretation Certification, for example, includes a detailed general knowledge exam, a test of specific information from the AWS Code book on radiographic quality and interpretation, and a practical exam testing the individual's ability to read radiographic films. Certification typically needs to be renewed after a period of nine years. AWS requires certification exams to be taken at an AWS accredited testing facility.
AWS Foundation
The AWS Foundation supports welding education through multiple scholarships and awards for students studying welding, welding engineering and materials science at the post secondary and graduate level. Scholarships are both need and merit based.
AWS Committees
- WEMCO - Welding Equipment Manufacturers Committee
- BSMC - Brazing and Soldering Manufacturers Committee
- PACWI - Pan American Coalition of Welding Institutes
- POCWA - Pacific Ocean Coalition of Welding Associations
- RWMA – Resistance Welding Manufacturing Alliance