Note: Weld symbols on the full reference line relates to welds on the near side of the plate. Click as many times as necessary to place multiple weld. 4-79, Symbols for Weld - ing and Nondestructive Testing, Including Brazing and revised again in 1986 with the title,. Description; Attached Files; Weld symbols. Find more similar flip PDFs like Flux Cored Arc Welding (z-lib. Austenitic weld-ring gaskets are also frequently used for flange joints made from CrMo steels with nickel-based cladding on the sealing surfaces. A groove (or butt) weld is a type of weld where parts are joined via a weld between a groove or gap (think of the groove joint discussed at the start). In this case the fillet weld has melt-thru, which in itself is not cause to reject the weld. The symbols for these grooves are nearly identical to the symbols that represent. 4-76, Symbols for Welding and Nondestructive Testing, was the first version of the combined documents and was prepared by the AWS Committee on Definitions and Symbols. the surface of contact between the pieces being connected) of the weld and a horizontal line where symbols are placed to describe the type of weld to be made. 1. Published on: 21 July 2023. Topic Welding Industry / General Welding Discussion / Sheet Metal Fusion Weld Symbol By yojimbo Date 09-10-2014 18:36. In many cases, when performing seal welds, the tube is welded to the tubesheet without the use of filler metal. 1, Section 2. Differential pressure cell b. 4-98). welDing symBols are Those DeFineD in aws a2. The most common letter symbols used are: S – Symbol for spot weld. Threaded fittings are used in non critical applications and when service fluid is at ambient temperatures such was instrument air, plant air, cooling water, potable water etc. 3. Check Pages 51-100 of Flux Cored Arc Welding (z-lib. Stich Welding is Also called Skip welding and they are mainly used to control the welding distortion, especially in sheet metal welding. 다음은 서포트에 대한 용접기호 예시입니다. Although you can apply it at different angles, it would be more prominent at 90 degrees. In other words, beveling is used in such a. The assembled “welding symbol” consists of the following eight elements, or any of these elements as necessary: reference line, arrow, basic weld. This gauge is a system used in order to call out sheet metal similar to that of electricians and wire. 1 Structural Welding Code—Steel, herein referred to as AWS D1. The maximum convexity allowed is 2mm for weld faces with a width of 8mm or less, 3mm for faces wider than 8mm but less than 25mm, and 5mm for faces wider than or equal to 25mm. This video goes over Welding Symbols & more specifically what Arrow Side & Other Side mean with regards to Welding Symbols. This chart can range from the largest gauge of carbon steel at #7 which is a decimal of . D1. The required weld size is the larger of that. A Bullet tack weld is a type of tack weld in which small pieces of metal are used to bridge large gaps during root run welding. First off, D1. 1 (a–h). This is the intent of 6. As per AWS D1. Welding Practice Test. But, I have seen it used to form the 'root' for SAW and other welding. In the mechanical and structural fields, seal welds are used most For structural and mechanical applications, a seal weld is used to prevent the inflow of fluid since it can cause harm, such as corrosion. They are symbolized by a vertical and a diagonal line ending at the bottom of each other (HV symbol) and a combination of the. 1, Sheet Metal Welding Code ASME IX ASME Section IX, Qualification Standard for Welding and Brazing Procedures, Welders, Brazers, and Welding and Brazing Operators D15. V Groove. A weld symbol is a pictorial profile that is attached to the reference line part of the Welding Symbol. It is commonly used for plastics and metals, and especially. welDing symBols are Those DeFineD in aws a2. Sometimes the detailer or engineer is ambiguous or wrong in the symbols. 1” Stud welds on the arrow side, 2” pitch, 20 total studs. Tack welds help keep the right alignment and distance between the parts that are being fused together. J. 0-2010 incluDes sTanDarD welDing The weld symbol is the little icon that is drawn on the reference line of the welding symbol. brackets, spigots and weld nuts to sheet metal where there is access from only one side and for making attachments to solid forged or machined parts. 1793” all the way to the smallest which. Weld symbols on the dashed line relates to weld on the far side of the plate. This engineering drawing present weld type symbols and fillet weld symbols. Standard Symbols for Welding, Brazing, and Nondestructive Examination. Laser beam welding ( LBW) is a welding technique used to join pieces of metal or thermoplastics through the use of a laser. a plate of 1/8 inches thickness made with a Square Groove Weld will have a weld size (s-throat size) of 1/8 inches. Shop or working drawings shall spec-ify the groove depths (S) applicable for the weld size (E) required for the welding process and position of welding to be used. Contact Us. Weld information for the “other side” is placed above the reference line. An . The symbol is interpreted as a simplified cross-section of the weld. The welding symbol is the whole thing, weld symbol and all. Seal Weld. 4-79, Symbols for Weld - ing and Nondestructive Testing, Including Brazing and revised again in 1986 with the title, Standard Symbols for Weld- Once in place, a fillet weld is used to create a strong seal between the two pieces. Weld-ring gaskets are usually made out of the same material as, or similar material to, pipes or flanges and are only used in pairs. 03" dia. Welders use plug weld symbols to show the amount, diameter, locations and spacing of the holes to be drilled. 5. The weld type symbol is typically placed above or below the center of the reference line, depending on which side of the joint it's on. SFLC STANDARD SPECIFICATION 0740 . Written by: Sandeep Kumar. In the Weldments box, select Welds. The panels of the fence are made up of HSS 2x2x3/16 capped both ends with a PL 1-3/4x1-3/4x1/8. The. For example. Arrow. This symbol is commonly used in welding blueprints and engineering drawings to specify that a PPW is required in a particular location. Excess weld metal refers to the metal that extends beyond the surface of a fillet or beyond a straight line connecting the toes of a butt/groove weld. You see a basic weld symbol on each welding. 6. If the welds are symmetrical on both sides of the plate the dashed. This welding doesn’t require much electricity and materials to be used making it a cheap process. It is the responsibility of the equipment user to determine whether NACE MR0175/ISO 15156-2 applies to these seal welds by referring to the Scope in Clause 1. Keeping them separate for clarification. Placement: The two workpieces are placed between the rotating electrode wheels of the seam welding machine. 4-76, Symbols for Welding and Nondestructive Testing, was the first version of the combined documents and was prepared by the AWS Committee on Definitions and Symbols. A complete Welding symbol may consist of additional information apart from the 3 main elements listed above. g. 1. 5 IDENTIFY the symbols used on engineering P&IDs for the following basic types of instrumentation: a. Studying this guide to welding symbols will help ensure you are one step closer to acing your next exam. 5. YouTube; LinkedIn; Facebook; Looking for something. This is important for welders to understand which side of the joint needs to be welded. Welding all around is often necessary in situations where the joint will be subjected to high pressure or needs to contain fluids or gases. We have done a contract design of a large welded frame and it includes a set of frame weldment drawings (several hundred sheets) that use multile arbitraily oriented views (done is NX3) with more multiple detail views pulled out to show the welded joints in "close-up" and then the weld symbols are applied to. This post covers What is Seal welding & seal welding symbols with examples. Surfacing welding is a process in which a layer of wear-resistant, corrosion-resistant, and heat-resistant metal is deposited on the surface or edge of a workpiece. The other essential part of the welding symbol is an arrow that connects to the reference line and points to the location where a weld is required. Edge weld symbols are most commonly associated with sheet metal or “gauge” material. My understanding is that the minimum welds sizes are intended to provided adequate fusion of the connected parts. 1 – Certification of Companies for Fusion Welding of Steel W59 – Welded Steel Construction (Metal Arc Welding) W186 – Welding of Reinforcing Bars in Reinforced Concrete. Projection welding is the most common method for nut and M- or T-thread bolt welding. Position of Arrow Line AWS A2. The symbol varies, depending on the geometry of the groove. Basic Weld Symbol The weld symbol always includes 1. This is a good workmanship practice but unless detailed properly it is not required. The contract may require seal welds on all steel backing. In the weld symbol shown below, this weld size is 1/8. It was revised in 1979 as A2. 04-15-2004, 09:26 PM. Take this free welding practice exam to get a sample of the types of questions on an actual welding exam. tail are required on a welding symbol. The Code ASME B31. By Joseph P. The melt through symbol, a hemisphere that is shaded in, is placed on the side of the reference line opposite the groove weld symbol. Figure 3. Resistance seam weld with no side significance, 8” pitch, 16” length. An arrow. 3-2) represents the weld symbol on drawings. The sonotrode is rotated along the weld seam. There may be multiple symbols for one fitting or part depending on the fashion it is to be installed (Butt weld, Socket Weld, Threaded. Threaded joints do not require to be seal welded if the joint is made for instrument connections or for piping components that expect cyclic removal for maintenance. You can remember the difference because weld symbols look like the weld you are making, and the welding symbol combines everything in one package. The P&ID is the primary schematic drawing used for laying out a process control system’s installation. Lindell Project. Finished by Machining. These symbols can be either letters or numbers. 2 Comments (2 New) Currently in the drawing of Creo Parametric 6 the weld symbols are generic symbol saved/hide in a system folder (System Syms). If the dashed line is above the full line, then the. The side of the joint to which the arrow points is the “arrow side” of the joint. Approved by the American National Standards Institute January 9, 2020. Cap Weld for welding of Cap on Pipes: Cap weld is a type of welding that is used to attach a cap, or metal disk, to the end of a pipe. The symbol includes the depth of the bevel and the groove angle. Weld symbols on the full reference line relates to welds on the arrow side of the plate being welded. The partial penetration welds are not as thick as the. 4:2020 revises the previous edition of the standard for welding symbols from 2012. ” The purpose of a seal weld may be to contain a fluid – either gaseous or liquid. 1 or CSA 59, the tail part of the welding symbol shall mention the joint type as ‘CJP’ as shown in the below welding symbol example for reference. Making Sense of Seal Welding Symbols Comparing Seal Welds with Other Welds Seal vs. The stem of the. " in the tail of the weld symbols. 0 and Section IX, Appendix I of the ASME Code. rmw (Mechanical) 28 Jun 05 15:26. Refer UG-37 of ASME Sec VIII div-1 2013 edition. Reading a welding blueprint is actually quite simple if you can decipher the angles and dimensions next to welding symbols. Created Date: 1/13/2012 8:35:12 AM The seal welds I'm accostumed to see are of three types: 1. A reference line (System A or B) A dotted (dashed) line parallel with a solid reference line (System A) An elementary and supplementary Weld Symbol. Resistance seam weld with no side significance, 8” pitch, 16” length. It is essential that the 'rules' of the standard used are correctly applied by drawing office personnel. Suppose the part under construction is shown in Fig 7. When the seal melts, it produces a. This symbol illustrates a convex contour finish. Type of Welding Joint: Butt Joint. SYMbOLS fOR WELDS can be found in the American Weld-ing Society publication Standard Symbols for Welding, Brazing and Nondestructive Examination (ANSI/AWS A2. 4:2007 An American National Standard Approved by the American National Standards Institute March 23, 2007Groove Welds. It is written down as a fraction of an inch. Once in place, a fillet weld is used to create a strong seal between the two pieces. There is no CO2 MIG welding with stainless steel. 1793” all the way to the smallest which is #28 at a decimal of. 030 hard wire and welded the caps all around with a standard "fillet" weld. Either a basic weld symbol or notations in the . 7. This engineering drawing present weld type symbols and fillet weld symbols. 0, 2010, Standard Welding Terms and Definitions. Units of measurement. , Armstrong A. D1. 2. The symbol may also include indications of the size or type of weld to be made. 1. Hayes The Lincoln Electric Company R. A symbol. 2 – Symbol for butt joint weld size. In the space below draw a symbol for the following: 3/16” spot weld on the arrow side, ground flush, a pitch of 2”, and 8 total welds. Butt weld. Welding definitions used in this document are in accordance with AWS Standard A3. NOTE 2 -Type of lines and line thicknesses should be in accordance with IS : 10714-1983. D1. 1. , Armstrong A. Other types of welds include flange welds, plug welds, slot welds, seam welds, surfacing welds, and backing welds. This method is often used to seal off the end of a pipe that has been cut or damaged or to fabricate small-diameter vessels. 1” Stud welds on the. , 2 inches), and the pitch (6 inches in the below example). That is, the weld penetrates from the toe (top) to the root (bottom) of the joint. Socket weld elbow 4. Note: Weld symbols on the full reference line relates to welds on the near side of the plate being welded. This typically involves two overlapping sheets or pieces of metal with the holes in the top one. The Reference Line. In. Plug and Slot Weld. Socket weld is a method where the pipe is inserted into a recessed area on the other piece of pipe. Understanding this symbol and the skills required to execute a CJP weld are crucial for welders, especially those working in industries where high-strength welds are required, like structural steel, shipbuilding, and heavy equipment manufacturing. Austenitic weld-ring gaskets are also frequently used for flange joints made from CrMo steels. 5 Added provisions for wrapping welds on opposite sides of a common plane to permit seal welding. A slot weld is similar to a plug weld except that the hole. There are 6 main groove welds: Square Groove. Bevel Groove. 20 inches or more, you can still obtain penetration without creating a groove bevel. Slot for Seal Weld: The slot for seal weld symbol consists of a square or rectangular slot with an “S” inside. Weld symbols on the dashed line relates to weld on the far side of the plate. Weld Beads. 1, is a comprehensive welding code governing the design of connections, including connection details, welding procedures. A reference line 3. (Laser Beam Welding) Tail Leader Elements in this area remain as shown when tail and arrow are reversed Basic weld symbol (Fillet weld on side of joint arrow is pointing to) (. Joints are combined with welds to make weld joints. They are typically made from small beads of the same material that will be used for your final weld. Apart from AWS A2. Welding: The welding machine applies both heat and pressure to the workpieces. The effective throat of a skewed T-joint in angles between 80° and 60° and in angles greater than 100° shall be taken as the shortest distance from the joint root to the weld face. A free blog to learn about welding symbols from basic to expert. Seal weld size: The weld size (a distance in the primary dimension " Units" or other units) to be applied to seal welds on base plates or cap plates. " a weld to be an end return with the weld proceeding around a corner slightly beyond the plane designated by the weld symbol. AWS D1. Some engineering companies even draw short ears on the hash marks to indicate a difference between screwed and socket-weld symbols (see Figure 3. Although not on print or spelled out in the tail or noted the engineer states verbally that corners shall have return. 1-WC XL:2020 WELDING SYMBOL CHART X-LARGE WALL SIZE. Construct a welding symbol in order to demonstrate an understanding of print interpretation; Explain the rules governing the use of the arrow, reference line, supplementary symbols, and combined welding symbols. The Arrow Side Welding Symbol consists of an arrow. Symbols are specified by national standards. What is a “seal weld?”AWS A3. 1M:2020 vii Advisors to the D1Q Committee on Steel (Continued) J. Welding & NDT Symbols kkhodaparasti@yahoo. MIG – Gas Metal Arc Welding (GMAW) MIG welding is a simple, popular form of welding, a novice can operate and master the art easily. )What is a Weld Symbol? According to AWS A3. Peripheral. A groove weld will be used when to parts come together in the same plane. SKA Weld Adapter KD Plastic Seal SV Bulkhead Union KDS Elastomeric Seal VKA1/ Test Point Connector, Pin M Tube Nut VKA3/ Test Point Connector, M16x2 OR O. 2 The welding symbol consists of a basic symbol and leader, and additional symbols such as an auxiliary symbol, supplementary symbol, and weld size symbol can be. It would appear that the wording is redundant if you have a weld symbol that specifies the type weld and a ground flush symbol. Sometimes the detailer or engineer is ambiguous or wrong in the symbols. For example, a weld symbol without a dimension and without CJP in its tail designates a weld that will other symbols, it is better co represent the weld on a separate sketch when symbolization becomes too difficult. The side of the joint to which the arrow points is the “arrow side” of the joint. 1, ISO 10628, and BS 5070 cover the standardization of P&ID symbols and guide process engineers in their. Welding Symbols with Typical TYP. Seal Neck Flange Dimensions EN 1092 (PN. —Electrode Selection Guide electric-arc welding. 1. le99 (Civil/Environmental) 7 Apr 22 22:16. Standard Symbols for Welding, Brazing, and Nondestructive Examination AWS A2. 11) round the periphery of a hole in one part so as to join it to the surface of the other part exposed through the hole. 4 Groove Welds. ~weld symbol is to specify the required strength of the joint required. N. The procedure of a fillet weld involves the positioning of the electrode at a 45-degree angle to the plate’s surface. If weld ring gaskets are used with auxiliary gaskets, the flange and bolt calculations must be carried out once for the weld ring gasket with the seal diameter to the outer-most seal seam and once for the auxiliary gasket. In most cases this is controlled by the diameter of the electrode. Key features of weld beads: Compatibility with all types of geometry, including bodies with gaps. com All welding symbols have 2basic parts: A reference line ( is always horizontal) An arrow ( is always inclined to the reference line at one end) The tail of the symbol is used for designating the welding and cutting process as well as the welding specifications, procedures, or the supplementary. The symbol is interpreted as a simplified cross-section of the weld. Sometimes detailers are too lazy to re-draw the drawings and you get stuck with the. (See cases 3 & 6 below) hokie66 (Structural) 8 Apr 22 05:44. g. When the first edition of AWS D1. Rogers BS 499: part 2. Weld-ring gaskets are usually made out of the same material as, or similar material to, pipes or flanges and are only used in pairs. g. 4-79, Symbols for Weld - ing and Nondestructive Testing, Including Brazing and revised again in 1986 with the title,. This opening made by gives the welder access to the total thickness of the material wall and allows him to create a uniform weld using multiple passes which guarantees the mechanical properties of the materials. 4 - 4. Due to more weld metal involved, the strength of the joint is high as compared to a single pass weld. In contrast, a welding symbol is the complete information package the designer wants to relay to the welder. Read more. 4 shown in below figure (right hand side). A DHV seam is welded from both sides and the roots meet. Single grooved and welded butt joint with backing strip: Full inspection efficiency of 0. As an example, I have recently made some serious changes in an engine oil pan for more clearence. Weld symbols pictorially represent the type of weld that the welding symbol is identifying. 5. Making Sense of Seal Welding Symbols. This gauge is a system used in order to call out sheet metal similar to that of electricians and wire. no allowance has been made for weld gaps or gasket thickness. The long-awaited revision of ISO 15614 Part 1, the ISO standard for the qualification of arc and gas welding procedures for steels and Nickel alloys, was completed in the first half of 2017. Position of Arrow Line In case of bevel -welded joint, the arrow line shall point towards the plate which is prepared. Easy-to-Learn. Hi Al Here is something for you and others related to seal welding since you mentioned it. Options for welding symbols are: Use the Welding. Per AISC, fillet weld terminations should be located approximately one weld size from the edge of the connection material to minimize notches. Done :)Following are some common mistaken assumptions on structural drawings regarding welding symbols. 3) between two overlapping parts made by depositing a fillet weld (2. The index lists the terms, symbols, and clauses that are used throughout the code, as well as the references to other standards and publications. 2. We would like to show you a description here but the site won’t allow us. Actually, tack welding is very important as it is used to hold the parts to be welded in the correct position and alignment while welding. Overall, there are three different possible positions for a weld symbol in the welding symbol: If the weld symbol is on the bottom side, the. 3 Preparation for Welding (E) Socket Weld Assembly says. You could still spot weld then laser the lap welds for an airtight seal. Three symbols shown below are the gate valve symbols used in isometric drawings. Double-Groove Weld Symbols The standard groove angles may be 45 degrees for bevel groove welds and 60 degrees for V-grooves Depth of Preparation and Groove Weld Size The groove weld size E is shown in brackets and the depth of preparation S is to the left of the groove weld size Single/Double PJP Groove Welds The achievement of the size (E). web-to-flange welds (Figure 3). 0, Standard Welding Symbols, and A2. . 4 carne into existence in 1976 as a result of combining and superseding two earlier documents, A2. 14. The advantages of symbols 5 f3 Welding symbols 1 Butt/groove welds The butt/groove welding symbols are shown in Fig. Although the main features of weld symbols are international, variations in detail occur from country to country. N. These seemingly cryptic symbols convey vital information about joint types, dimensions, and welding techniques, bridging the gap between design intent and real-world execution. weld (2. A free AutoCAD DWG file download. When identification of the weld process is required as part of the weld symbol the relevant weld process code is listed in BS EN ISO 4063. When welding on thick material, the weld will not penetrate through the thickness ofDecember 21, 2017. Read More . The diameter symbol, Ø, is no longer a part of the plug weld symbol. However, in certain cases, filler metal may be employed. Piping Symbols. The detailer then makes up the detail drawings (Shop Drawings)and sizes the weld to the AISC Standard. See full list on millerwelds. Pipe 3. 용접 길이는 별도 표로 작성되어 기호에 넣지 않은 것이다. 70. A symbol Note: Weld symbols on the full reference line relates to welds on the near side of the plate being welded. The slot weld symbol is the same that is. The Tail. A joint made from both sides has a symbol on each side of the reference line. 00. Module 4: Weld Symbols: Spot and Projection, Stud, Seam, Back and Backing,. 1/4” stud welds on the arrow side with a. JJF (Structural) 10 Mar 05 17:14. This type of welding is often used to join pipes or other cylindrical objects (e. pdfAWS A2. 3. The heat is generated by electrical resistance as current. 5mm. 3. org). This type of welding technique is used to connect socket weld fittings or slip on flanges to pipes. A full penetration weld, also known as complete joint penetration (“CJP”), involves a special kind of groove that allows filler material to fill the entire joint gap. Figure 8. This symbol represents: Plug Weld. Yes. A welding symbol is made from a standardized library of symbols and elements, which when assembled together, convey specific welding information. 1. Fillet weld 5. It makes it a clean and safe process than many others. CJP weld joint must be clearly identified on the welding drawing. Symbol Description Symbol Description Symbol Description Symbol Description Symbol Description Symbol Description Symbol Description . If you’re a welder, a fabricator, an engineer, or someone who frequently. Convex. 5 Fatigue curve cases and figures revised to agree with AISC 360. A circumferential weld is a type of welding that joins two circular pieces of metal together in a circular fashion. The minimum elements required to create a welding symbol are the reference line, arrow and the weld symbol. If a weld is to be applied to both sides of the joint this is called a double groove weld. The welding symbol without dimensions designates a PJP weld with minimum effective weld size as specified by the AASHTO/AWS D1. If youre using seal weld to add strenght to the joint then youre using it for the wrong reason. Socket Weld vs. One of the most important welding symbols is the fillet weld. The symbol for a CJP weld is quite simple – it’s a single bevel symbol (an inverted ‘V’) or a square groove symbol or any other. g. 1” Stud welds on the arrow side, 2” pitch, 20 total studs. Fillet welds that are to be made flat-faced by mechanical means must be shown by adding both the flush contour symbol and the user’s standard finish symbol to the weld symbol. 1 Commentary (3) Seal Welded Steel Backing. basic weld symbols,. Socket welding (SW) is used for welding pipes and fittings including reducers, tees and elbows. 1 2015 does indeed have new language regarding seal welding. It is of small use to the engineer, since it is difficult to include on it all the details and dimensions. 5. A welding symbol uses ‘ weld symbols ‘ to convey the type. The symbol is interpreted as a simplified cross-section of the weld. dwg Use AutoCAD Mechanical to create weld symbols. cso car seal open csc car seal closed reducer union drain valve closed spec blind open spec blind 25 insulation orifice meter coriolis meter psv valve quick change orifice turbine meter static mixer mass flow meter m magnetic flow meter rotameter pvrv angle valve conical strainer insulation kit t weld tie-in nps/metric o. It provides structural integrity, enhances strength, and can help create a leak-proof seal. We would like to show you a description here but the site won’t allow us. The weld type symbol is typically placed above or below the center of the reference line, depending on which side of the joint it's on. solid indicates nun-nuclear safety class 2 i nns-clzi orifice 2. In the case of the bevel or J-groove weld symbol, the arrow shall always point with a break depicted toward the member. 3 = Welding Symbol. The symbol is typically a semi-circle and is used on engineering drawings and blueprints to communicate the specific requirements for the. Ceramic backings are made of a high-temperature resistant ceramic seal, a mixture of different mixed minerals like Al2O3, SiO2, Fe2O3, TiO2, etc. A weld symbol. Furthermore, the electrode should be tilted 15 degrees to the direction of. Welding Symbols with Typical TYP. Groove weld symbols tell the welder what type of groove is needed. The tube protrudes say 3 millimeters (or less) beyond the tubesheet and the end is flare. Welding symbols. Tail (Optional part)- V-shaped part of the welding symbol. g. fm Author: Default Created Date: 7/25/2001 8:48:45 AM Published on 6 January 2020. It’s a weld joint with one side face being thicker than the other side face. For architecturally exposed steel that is to be painted, seal welds may be specified to prevent unsight-ly rust bleeding. We have 1/4" plate lapped onto a C15 and the detail drawings have a typical fillet weld symbol with a 1/4" size. Title: A21-desk. D1. It would appear that the wording is redundant if you have a weld symbol that specifies the type weld and a ground flush symbol. 3M, Specification for Welding Sheet Steel in Structures, was developed and issued in 1978, it was anticipated that changes would be needed in the specification as further research was conducted onWelding Symbols Although the basic symbol system is uniform, there is a need for some flexibility, as specific circumstances differ from one shop to another and field operations may involve entirely different situations.