CWB Welding Course Notes - PDF

Here is the converted text from the images into a structured markdown format. ## 1.1 Types of Joints There are five basic joints used in welding: **JDPR-302 - Joint Design and Preparation** The corner, lap, and T-joints are the types that require fillet welds. The edge joint is mainly used on l...

Here is the converted text from the images into a structured markdown format. ## 1.1 Types of Joints There are five basic joints used in welding: **JDPR-302 - Joint Design and Preparation** The corner, lap, and T-joints are the types that require fillet welds. The edge joint is mainly used on light-gauge sheet metal and does not normally require additional filler metal. Select the faying surface for each type of joint given below. | | | | | :-------------: | :-------------: | :-------------: | | Butt joint | T-joint | Edge joint | | Lap joint | Corner joint | | ## 1.2 T-Joints T-joints join two pieces of metal at right angles ($90°$) to each other. The square T-joint requires no edge preparation. T-joints are widely used due to their low cost and ease of fit. Various T-joints ## 1.3 Lap Joints Lap joints are often used for welds joining two materials of different thicknesses. Lap joints need little or no edge preparation. On thicker material, the edges might be prepared with a single bevel, double bevel, single J, or double J, depending on loading condition, distortion allowance, and filler weld material. | | | | | | :-------------: |:-------------:| :-------------:| :-------------:| | Single bevel | Double bevel | Single J | Double J | CSA W59 states: *The minimum overlap of parts shall be five times the thickness of the thinner part joined and not less than 25 mm (1 in) while the gap between the mating surfaces should not exceed 2 mm (1/16 in).* * If a weld does not need great strength, a single lap joint might be enough to provide a "tight" joint. * If the weld will be subjected to fluctuating, bending, or twisting loads, then both sides of the joint should be welded. ## 1.4 Corner Joints A corner joint joins two pieces at right angles, with the joint is formed at the ends of both pieces, creating an L shape. Various open corner joints There are two types of corner joints: the open corner and the closed corner. Follow these steps when welding corner joints used in heavy stress-loading applications: 1. Weld the joint from the inside 2. Gouge to sound metal from the outside 3. Weld from the outside * The open corner joint is more often used due to its excellent penetration. * The closed corner joint is normally recommended for light-gauge sheet metal | Types | Corner Joint | | :-------------: |:-------------: | |Open| $\boxed{ ٦٨٨ }$| |Closed| $\boxed{ Closed }$| For thicker material, prepare the edge of one or both pieces and allow for a small root opening. This helps to ensure full joint penetration. | Types | Edge Preparation | | :-------------: |:-------------: | |Single Bevel| $\boxed{극극극}$| |Single V| $\boxed{극극극}$| |Double Bevel| $\boxed{극극극}$| |Single J| $\boxed{극극극}$| |Single U| $\boxed{극극극}$| |Double J| $\boxed{극극극}$| ## 1.5 Edge and Flanged Joints An edge joint connects two pieces of metal that are turned up at the edges. Edge joints are mostly used on light-gauge material, such as sheet metal. The edges of the sheet metal can be turned up with a piece of metal-forming equipment called a brake. The turned-up edges reduce the danger of burn-through on thin metal and help to prevent distortion. On thin metal, no additional filler metal is required. With plate, the edges must be prepared to ensure sufficient penetration. Edge joint preparations A flange weld is one in which at least one of the members has a flanged edge shape at the joint. In the structural applications of joint types, a flanged joint (sometimes referred to as a flanged weld) is considered to be a projecting ridge, rim, collar, or ring on an object such as a column, beam, pipe, or ridge-formed material that provides additional strength, stiffness, or surface area for the attachment of, or to, another object. Flanges can occur on any of the joints mentioned previously, as shown below. | Types | Edge Joint | | :-------------: |:-------------: | |Edge preparations| $\boxed{\rightharpoonup Edge Weld}$| |Edge preparations| $\boxed{Edge weld in a flanged butt joint}$| |Edge preparations| $\boxed{Edge weld in a flanged corner joint}$| |Edge preparations in the form of | Single bevel, Single V, Single j, Single U| |ADVANTAGE OF A FLANGED JOINT| DISADVANTAGE OF A FLANGED JOINT | |:-------------| :-------------| | Increased strength| Higher cost consideration for formed materials | Match each flange fit-up with its correct joint configuration |Butt Joint|T-Joint| Lap Joint| |:-------------:|:-------------:|:-------------:| |Corner Joint| Edge Joint|| There are many uses in design for flanged joints. Some of the common uses for flanged materials are in the construction and fabrication of the following: * buildings and bridges * crane rails * construction cranes * other lattice structural designs Flanged materials benefit from the strength incurred from the structural design of a flange web configuration. They are used as ridge materials for sealing surfaces of access points in various types of low-pressure tank applications. ## 1.6 Butt Joints A butt joint is formed when two pieces of metal are beside each other in the same plane. This type of joint is widely used because it is strong and can be joined relatively easily. Different edge preparations can be used depending on the thickness of the material to be welded. |SQUARE GROOVE WELD|SINGLE V- GROOVE WELD |GROOVE WELD WITH MULTIPLE KEYHOLE PASSES| |:-------------|:-------------| :-------------| |Groove angle| Bevel angle| Root Face| |Thickness (t)|Root opening| | The single V-groove weld is normally used on thicker material up to 19 mm (_3/4_ in). Preparation can be performed with an oxy-fuel cutting torch or with a grinder. The heat must penetrate the joint completely to achieve full strength. There should be a keyhole at the leading edge of the weld indicating that the weld puddle has melted through to the bottom edge of the base metal. The square groove weld requires no edge preparation. Square groove butt joints are only suitable with the oxy-acetylene welding process for material 3.2 mm (_1/8_ in) or less. A small gap about the thickness of the plate should be used when fitting the joint. A convenient method of setting an appropriate gap is using the filler rod to physically set the plates apart. If multiple passes are required to weld a joint in thick plate or pipe, the first root pass is the most important. There should be complete fusion, penetration, and reinforcement. Additional passes are called fill passes, and the final pass to provide the reinforcement at the top (cap) is known as the cap pass. The cap pass should provide a slightly convex bead. ## 1.7 Variations in Joint Design The edge of weld joints can be prepared in several ways. The following factors affect the choice of edge preparation: Corner Joint |Type Of Welds| | |:-------------|:-------------| | Flare Bevel Groove | Spot | | Square Groove | Projection | | V-Groove | Seam | | Bevel Groove | Braze | | U-Groove || | J-Groove || | Flare V-Groove || | Edge Flange || |Coner Fillet|| | Fillet Corner Joint |T-Joint| | |:-------------| :| |Type Of Welds|| | Fillet | Flare Bevel Groove| | Plug | Spot | | Slot | Projection | |Square Groove| Seam | |bevel Groove| Braze | Square Groove |butt joints| | |:-------------|:-------------| |Types Of Welds|| | Flare V-Groove | Flare V-Groove | | Square Groove | Edge Flange | | V-Groove | Braze | |Bevel Groove|| |U- Groove|| |J- Groove|| *Material, Welding Process, Thickness * Extent of Penetration required *Factors that affect the choice of edge preparation *The way the load is applied ( e.g. Sudden , variable or steady) * welding distortion allowance Cost * Type of Load applied to the weld **(e.g. compression, torsion, bending, or fatique)** Drag the plates provided into the labelled boxes to assemble the desired fit-up joints. *There are enough pieces of each shape to assemblie the joint. *Pieces placed in the wrong box or in the wrong location in a box will snap back. *If run out of pieces you probably stacked some on top of to each other. | But joint | T- Joint |Lap Joint | |:-------------: |:-------------:|:-------------:| |Edge Joint | Corner Joint | | ## Lesson 2: Weld Types **Common Type of Welds** A weld is the merging of materials by applying a sufficient amount of heat ( or pressure). Quite often a filler material is used , but in some cases, it is not. There are different types of welds that serve different purposes. The following are the most common types. | Surfacing welds | Fillet welds | | ------------- |:------------- | |Groove welds| Tack Welds | |Plug and slot welds | | Plug Welds | |Slot welds | Loader Bucket _Drill collar_ _Surfacing by arc welding_ `Example of surfacing Welds on loader bucket teeth` `Example of surfacing Welds on a pipe` **Surfacing Wells Terminology** _Buildup_:`A change of dimensions, such as thickness` `Example of buildup on a plate` *Buttering*: Build up intended to provide a buffer or a transition another surface well Example of buttering used For stainless steel _Hardfacing_: to create a hard for tough surface to control wear. _Example Of Hardfacing Welds On A Loader Bucket_. *each tack weld is a short weld about 13 1/2 in long the 12 Welds can be temporary of permanent. *Cladding*: to create corrosion-resistant or heat-resistant layer example of clad in inside of a pope tack welding T joint tag weld. **Guidelines for Tack Welds** *(USE SMALL WELDS).* *plan tacking Sequences.* Ensure metal compatibility "Stack wells that incorporate it to the final world shall be mad with electrodes meeting the requirement of the final wells and shall be subject to the same. Quality requirements"" *Dont lit or turn "Avoid Craters". ## 2.3 Edge Welds An edge weld is a weld in an edge joint, a flanged butt joint , or a flanged corner joint in which the full thickness of the members are fused. Edge welds neither groove welds nor fillet welds They or not sur facing Welds. Ether because they for M ajoint along two members, `Plug weld`. *Plus wells, A circular hole is main in one member of Ajoint The well is placed inside.*** *Is slot Weld in one Member of ajo int.the main in all Member of Ajoint.. "Plug and slot welded can be filled completely all left and field with the inside field being" Weld Around the plug in slot the joint is after unnecessary.*** *As that in a 12 extra heat distortion or wasted thinned material.these wells can made with 8 hole or slots and are called*. *arc sport and are seems and in with the upper ship in melted and filled to the lower sheetedge edge wedge*. Is edge weld flange butt joint edge Edge. ### 2.5 Fillet Welds A fillet weld has a roughly triangular cross-section. It joins two surfaces approximately at right angles to each other. | | | | | :-------------: | :-------------: |:-------------: | |Fillet Welds| **Strength** Leg Length & Size, Face leg Length,& Size | Types and characteristic | | Actual Leg Lengths throat ,con cavity concavity Leg Lengths And Size | Size ,toe | Applications | | Root Penetration |Root|| *Toe Theoretical throat and Effective throat