WELDING INSPECTION BOOK
Reasonable care is taken in the compilation and publication of the Welding Inspection Hand- book to ensure authenticity of the contents. However, no. This book was recommended to me by a co-worker and he loaned it to me to look through for awhile. I decided that since it had such great material in it that I. Welding Inspection Handbook [AWS Committee on Methods of Inspection] on pixia-club.info *FREE* shipping on qualifying offers. One of the best books on.
|Language:||English, Spanish, German|
|ePub File Size:||21.62 MB|
|PDF File Size:||18.44 MB|
|Distribution:||Free* [*Regsitration Required]|
This Part B Book of Specifications is intended to be used as a and document reviews performed by the Certified Welding Inspector (CWI). A concise and accessible guide to the knowledge required to fulfil the role of a welding inspector. In covering both European and. This book has been invaluable to literally thousands of CWI applicants who studied on their own for the AWS CWI pixia-club.info to prepare for AWS welding inspector.
A quick look at the American Welding Society job board at the time of this writing showed 10 out of 24 job openings were for inspectors or quality control personnel.
ENSURING STRONG BONDS
A search on CareerBuilder. The job locations spanned the U. Good compensation and plenty of opportunities for those interested in becoming a certified welding inspector CWI are expected to continue for the foreseeable future.
The course stretches for two weeks, but even when that is done, the instructors might stretch it out a day or two see Figure 1. So what does a CWI have to know? It helps to know a little bit about everything. Depending on which codes for example, D1. They need to know about welding processes, terminology, and symbols and how different materials react during the welding process. They need to learn about nondestructive testing and visual clues that suggest a weld is acceptable or not.
Experience Counts As Cameron found out, welding experience is helpful.
AWS is serious enough about the work experience requirement that it asks for written verification of documented employment when someone submits an application to take the CWI exam. If acquiring the proof of employment experience is not possible, then the applicant has to provide a detailed affidavit that confirms any previous work experience.
With experience in oil rig fabrication, mining equipment repair, construction, and manufacturing, Cameron said he has worked with just about every welding process imaginable and has learned to weld to multiple codes.
Check back soon for Part 2 on this topic, which will cover ways to help you assess and bridge the gap between how much you know and what you need to know, as well as give you information on the CWI Pre-Seminar, seminars, and methods of self-study. Please see this AWS landing page to find the right contacts in Nigeria: Me parece muy interesante e Importante para todos aquellos que quieren y les gusta la Soldadura!
Como puedo hacer para poder realizar esta preparatoria y posterior el de inspector. Espero sus respuesta favorable. Por favor Vea esta pagina para informacion sobre los centros de aprendizaje y de certificacion mexicanos asociados con AWS. And I am taking the test on Saturday following the seminar. I have been wondering besides the seminar, what other things should I be studying or reviewing to be more prepared?
Make sure to check out the QC1 and B5. I have been reading about the 72 hour online pre exam,my question is will the online course get you ready and give you the information you need to pass exam?
Weld Inspector (WI) Level 2
I am interested in obtaining information regarding to nine year CWI renewal by endors ments. What and where are the seminars offer, if I choose to attend. Please see this page for information about endorsements: I will be preparing to retake my test after failing back in Oct. Should i study D1. Any other pointer will be very much appreciated, Thank you very much in Advance!
My brother is a welder, ans I think that getting this certification would be a good career step for him. Do most takers use up the entire two hours allotted for each section?
This sounds like a very intense exam! How long is the certification good for? Thanks for this information! I need more in depth training on the D1. Is there anyone or any place that does this type of training? I took the AWS seminar twice thinking that they would know the most of what training is required in order to pass the exam but obviously that did not happen. So I need help. Estoy interesado en llevar el curso para ser inspector.
O puede resolver ambas versiones, Usted decide. The surface of a fusion weld exposed on the side from which the weld has been made. The zone on the side of the first run furthest from the welder. The boundary between a weld face and the parent metal or between runs. This is a very important feature of a weld since toes are points of high stress concentration and often they are initiation points for different types of cracks eg fatigue cracks, cold cracks.
In order to reduce the stress concentration, toes must blend smoothly into the parent metal surface.
Excess weld metal: Weld metal lying outside the plane joining the toes. Other non-standard terms for this feature: Reinforcement, overfill. For an MMA weld on carbon steel plates, the angle is: Included angle The angle between the planes of the fusion faces of parts to be welded. In the case of single V or U and double V or U this angle is twice the bevel angle. In the case of single or double bevel, single or double J bevel, the included angle is equal to the bevel angle.
Root face The portion of a fusion face at the root that is not bevelled or grooved. Gap The minimum distance at any cross section between edges, ends or surfaces to be joined. Its value depends on the welding process used and application; for a full penetration weld on carbon steel plates, it has a value between mm.
Root radius The radius of the curved portion of the fusion face in a component prepared for a single J or U, double J or U weld. Land The straight portion of a fusion face between the root face and the curved part of a J or U preparation, can be 0. Usually present in weld preparations for MIG welding of aluminium alloys. If the root gap is zero ie if components are in contact , this preparation becomes a closed square butt preparation not recommended due to the lack of penetration problems!
Included angle Angle of bevel Gap Root face Single V preparation The V preparation is one of the most common preparations used in welding; it can be produced using flame or plasma cutting cheap and fast. For thicker plates a double V preparation is preferred since it requires less filler material to complete the joint and the residual stresses can be balanced on both sides of the joint resulting in lower angular distortion.
This asymmetric preparation allows for a balanced welding sequence with root back gouging, giving lower angular distortions. Whilst single V preparation allows welding from one side, double V preparation requires access to both sides the same applies for all double side preparations. However, tighter tolerances obtained in this case provide for a better fit-up than in the case of V preparations. Usually it is applied to thicker plates compared with single V preparation as it requires less filler material to complete the joint and this leads to lower residual stresses and distortions.
Similar to the V preparation, in the case of very thick sections a double U preparation can be used. Double U preparation Usually this type of preparation does not require a land exception: Backing strips can be permanent or temporary. Permanent types are made of the same material as being joined and are tack welded in place. The main problems related to this type of weld are poor fatigue resistance and the probability of crevice corrosion between the parent metal and the backing strip.
It is also difficult to examine by NDT due to the built-in crevice at the root of the joint. Temporary types include copper strips, ceramic tiles and fluxes. Double preparations are recommended in the case of thick sections. The main advantage of these preparations is that only one component is prepared cheap, can allow for small misalignments. The metal melted or deposited during one passage of an electrode, torch or blowpipe.
Single run weld Multi run weld Layer: A stratum of weld metal consisting of one or more runs. Single side weld 6 Double side weld Fillet Weld A fusion weld, other than a butt, edge or fusion spot weld, which is approximately triangular in transverse cross section. The perpendicular distance between two lines, each parallel to a line joining the outer toes, one being a tangent at the weld face and the other being through the furthermost point of fusion penetration Design throat thickness: The minimum dimension of throat thickness used for purposes of design.
Also known as effective throat thickness. The distance from the actual or projected intersection of the fusion faces and the toe of a fillet weld, measured across the fusion face. A flat face fillet weld in which the leg lengths are equal within the agreed tolerance. The relation between design throat thickness and leg length is: Convex fillet weld: A fillet weld in which the weld face is convex. The above relation between the leg length and the design throat thickness written for mitre fillet welds is also valid for this type of weld.
A Quick Guide to Welding and Weld Inspection
Since there is excess weld metal present in this case, the actual throat thickness is bigger than the design throat thickness. Concave fillet weld: A fillet weld in which the weld face is concave.
The relation between the leg length and the design throat thickness specified for mitre fillet welds is not valid for this type of weld. Also, the design throat thickness is equal to the actual throat thickness. Due to the smooth blending between the weld face and the surrounding parent material, the stress concentration effect at the toes of the weld is reduced compared with the previous type.
This is why this type of weld is highly desired in case of applications subjected to cyclic loads where fatigue phenomena might be a major cause for failure. A fillet weld in which the vertical leg length is not equal to the horizontal leg length. The relation between the leg length and design throat thickness is no longer valid for this type of weld because the cross section is not an isosceles triangle.
Horizontal leg size Vertical leg size Throat size Deep penetration fillet weld: A fillet weld with a deeper than normal penetration. This type of weld uses the benefits of greater arc penetration to obtain the required throat thickness whilst reducing the amount of deposited metal needed, thus leading to a reduction in residual stress level. In order to produce a consistent and constant penetration, the travel speed must be kept constant, at a high value.
As a consequence, this type of weld is usually produced using mechanised or automatic welding processes. Also, the high depth-to-width ratio increases the probability of solidification centreline cracking.
Fillet welds added on top of the groove welds improve the blending of the weld face towards the parent metal surface and reduce the stress concentration at the toes of the weld.
The orientation of a weld expressed in terms of working position, weld slope and weld rotation for further details, please see ISO Weld slope: The angle between root line and the positive X axis of the horizontal reference plane, measured in mathematically positive direction ie counter-clockwise. Weld rotation: The angle between the centreline of the weld and the positive Z axis or a line parallel to the Y axis, measured in the mathematically positive direction ie counter-clockwise in the plane of the transverse cross section of the weld in question.
Sketch Flat A welding position in which the welding is horizontal applicable in case of fillet welds. PB Horizontalvertical A welding position in which the welding is horizontal, with the centreline of the weld horizontal.
PC Horizontal A welding position in which the welding is upwards. Vertical-up PG A welding position in which the welding is downwards. A welding position in which the welding is horizontal and overhead applicable in case of fillet welds.
This technique is generally used in vertical-up welds. Stringer bead: A run of weld metal made with little or no weaving motion.
An unacceptable imperfection. This standard classifies the geometric imperfections in case of fusion welding, dividing them into six groups: An imperfection produced by a local rupture in the solid state, which may arise from the effect of cooling or stresses.
Cracks are more significant than other types of imperfection, as their geometry produces a very large stress concentration at the crack tip, making them more likely to cause fracture. Types of crack: Radiating cracks radiating from a common point. Branching a group of connected cracks originating from a common crack. These cracks can be situated in the: Crater cracks are found only in the weld metal. Depending on their nature, these cracks can be: Lamellar tearing. Hot cracks Depending on their location and mode of occurrence, hot cracks can be: Occur in the weld metal usually along the centreline of the weld as a result of the solidification process Liquation cracks: Occur in the coarse grain HAZ, in the near vicinity of the fusion line as a result of heating the material to an elevated temperature, high enough to produce liquation of the low melting point constituents placed on grain boundaries.
Solidification cracks Generally, solidification cracking can occur when: The depth-to-width ratio of the solidifying weld bead is large deep and narrow. Solidification cracking is most likely to occur in compositions, which result in a wide freezing temperature range. In steels this is commonly created by a higher than normal content of carbon and impurity elements such as sulphur and phosphorus.
These elements segregate during solidification, so that intergranular liquid films remain after the bulk of the weld has solidified. The thermal shrinkage of the cooling weld bead can cause these to rupture and form a crack. Scale can have a high sulphur content, and oil and grease can supply both carbon and sulphur. Contamination with low melting point metals such as copper, tin, lead, and zinc should also be avoided.
Underbead cracking lies parallel to the fusion boundary, and its path is usually a combination of intergranular and transgranular cracking. The direction of the principal residual tensile stress can, for toe cracks, cause the crack path to grow progressively away from the fusion boundary towards a region of lower sensitivity to hydrogen cracking.
When this happens, the crack growth rate decreases and eventually arrests. A combination of four factors is necessary to cause HAZ hydrogen cracking: Therefore, cracking can be avoided through control of one or more of these factors: Maintain a specific interpass temperature same effect as preheat. Postheat on completion of welding to reduce the hydrogen content by allowing hydrogen to effuse from the weld area.
Apply PWHT to reduce residual stress and eliminate susceptible microstructures. Use multi- instead of single-run technique eliminate susceptible microstructures by means of self-tempering effect, reduce the hydrogen content by allowing hydrogen to effuse from the weld area. Use a temper bead or hot pass technique same effect as above. Use austenitic or nickel filler avoid susceptible microstructure formation and allow hydrogen diffusion out of critical areas.
Use dry shielding gases reduce hydrogen content. Clean rust from joint avoid hydrogen contamination from moisture present in the rust.
Reduce residual stress. Blend the weld profile reduce stress concentration at the toes of the weld. Cracking occurs in joints where: With further strain, the vertical parts of the cracking are produced, generally by ductile shear cracking.
These two stages create the terraced appearance of these cracks. Two main options are available to control the problem in welded joints liable to lamellar tearing: A combination of joint design, restraint control and welding sequence to minimise the risk of cracking.
Gas cavity can be present in various forms: Causes Gross contamination of preparation surface Laminated work surface Crevices in work surface due to joint geometry Prevention Introduce preweld cleaning procedures Replace parent material with an unlaminated piece Eliminate joint shapes which produce crevices Comments Worm holes are caused by the progressive entrapment of gas between the solidifying metal crystals dendrites producing characteristic elongated pores of circular cross-section.
These elongated pores can appear as a herring-bone array on a radiograph. Some of them may break the surface of the weld. The main cause is shrinkage during solidification.
Causes Lack of welder skill due to using processes with too high a current Inoperative crater filler slope out TIG Prevention Retrain welder Use correct crater filling techniques Comments Crater filling is a particular problem in TIG welding due to its low heat input.
To fill the crater for this process it is necessary to reduce the weld current slope out in a series of descending steps until the arc is extinguished.
The imperfection is an irregular shape and thus differs in appearance from a gas pore. These only become a problem when large or sharp-edged inclusions are produced.
The imperfection is of an irregular shape and thus differs in appearance from a gas pore. Adjust welding parameters ie current, voltage etc to produce satisfactory welding conditions Oxide inclusions Description Oxides trapped during welding.
This type of defect occurs especially in the case of aluminium alloys. Gross oxide film enfoldment can occur due to a combination of unsatisfactory protection from atmospheric contamination and turbulence in the weld pool. Lack of fusion Lack of sidewall fusion 5. Causes Low arc current resulting in low fluidity of weld pool Too high a travel speed Inaccurate bead placement Prevention Increase current Reduce travel speed Retrain welder Comments Lack of inter-run fusion produces crevices between the weld beads and causes local entrapment of slag.
Causes Low heat input Excessive inductance in MAG dip transfer welding, MMA electrode too large low current density Use of vertical down welding Large root face Small root gap Incorrect angle or incorrect electrode manipulation Excessive misalignment at root 5. In this case incomplete root penetration is considered part of this structure and is not an imperfection this would normally be determined by the design or code requirement.
When examined from the root side, you can clearly see one or both of the root edges unmelted. Causes and prevention Same as for lack of root fusion. It is characterised by its depth, length and sharpness. If the bead of a repair weld is too small, the cooling rate following welding will be excessive and the parent metal may have an increased hardness and the weld may be susceptible to hydrogen cracking.Get them.
The CWI exam is created by industry experts, and documented in two standards: EN Destructive tests on welds in metallic materials — transverse tensile test. The welding plant controls both travel speed and arc gap but under constant supervision.
Test reports should also give a description of the appearance of the fracture and location of any imperfection 2.