Deg Weldments 6g6h5q

Deg Weldment's The designer or engineer faces many questions when deg welded structures, at one time the approach was to design from past experience, it's easy or so it might seem. Using a design that already exists has great merit, much of the work may be done leaving you to modify or tweak the design, but invariably you will also inherit all of the designs flaws, an old design may be out dated, overbuilt, expensive. Today these methods are largely discarded, replaced by a more systematic approach to design. Most modern designs rely on calculations and mathematical equations to factor in the forces at work in order to come up with an efficient plan. For the bulk of our study we will use steel as our material in question, although there is wide array of other materials steel remains the most common and cost effective, commercial availability is great and its mechanical properties make it a good choice. When beginning a design you must select an approach to your plan, much of this is done without thinking too much, the choice may be assigned to you or your gut feeling and investigations may lead you along. The biggest decision may be to choose a redesign of an entire product or possibly" a tune up “cleaning up a section or adding a new feature for example. Below I've compiled a list of guidelines to assist you in the efficient use of Steel, these 15 or so elements are a systematic approach to deg by either section or complete assembly.

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Recognize the problem (why are we doing this? To improve or invent

 Analyze a present design (how did it perform? Warranty, customer , sales people & market demand)

 Determine Load criteria(what’s its purpose)  Major design considerations(Aesthetics, Weight, Material, Cost)  Layout of fabricated components  Plate and stock considerations and preparation  Special sections and Forming options  Weld t design

 The size and amount of weld filler material  Use of Sub-Assemblies Assembly Considerations Control & correction of distortion

 Cleaning and Inspection We will investigate and discuss each of these topics in order to get a basic understanding of what the designer must do in order to fulfill his or her obligation.

 Recognizing the reason: As we begin to plan our design we must ask what the goal is for the project, ether there is a product in place already that served its purpose well and needs a facelift such as a diet, new look, or perhaps beefing up to increase rigidity or load carrying capability. It may be that we’ve been asked to build a completely new product from the ground up, although considerably more work, this has advantages in that there are no predisposed notions, it's a clean slate for the designer to use his or her imagination.

 The Existing Design: If we are asked to modify or improve a design already in production how should we approach this in a logical manner? Investigate all we can about its past performance! In the original incarnation was the product larger, heavier or more ridged than its service life really required. Could we check service records for warranty claims, failures, customer , sales and marketing data for clues as to what is really necessary for effective redesign? Ask what features must be retained and what features must be added? The Load Factors

 Every designed part has necessity, but what is its job? What work will it be asked to perform, and in what type of conditions. Understanding the service environment is crucial in design of weldment's, Loads are perhaps the principal factor in design, like static and dynamic or impact give clues to the physical stress the parts must withstand without failure. Five types of stress must be considered when deg welded structure, Torsional, Tensile, Compressive, Bending &Shear stress as well as variables such as safety factors, vibration, temperature and

overloads. When searching for a place to start look to loads for ideas, an engines speed can determine torque on a shaft, weight on a structure, wind shear on a building, if the factors aren't clear use an assumed load and test as you go.

 Major Design Factors: In order to achieve a goal of producing a part at the lowest overall cost it's necessary to evaluate the design to make certain optimum use is made of metallurgical and physical properties of the materials. Factors include: material and labor  Safety factor's should be sufficient but too large a margin again adds cost

 Appearance should be pleasing but in hidden areas consider cheaper grades of steel( hot rolled metal is just as strong as cold rolled for a fraction of the cost)

 Analyze the use of stiffeners to replace material thickness, this reduces weight and cost

 Using the most cost effective material, higher carbon content steels or addition of alloying makes forming harder and preheating necessary

 Use as much stock steel sizes as possible, specialty materials slow down delivery and increase cost.  Always keep in mind accessibility for welders and mechanics for part replacement or service.

 Layout of parts: Whenever possible make your designs as easy to handle with standard tooling, use as few individual parts as possible to reduce welding and machine time When producing parts for weldmt’s try and nest parts in a series in order to take advantage of every inch of the raw material as possible, as little scrap as possible. Keep section shapes round ,rectangular, this makes it easier to program for machining and robotic welding.

 Plate Preparation: Plate preparation is the basis for all fabrication with steel; many methods are available with economy being determined by several factors, material selection, quantity, equipment available, but cost is normally the deciding factor. We should decide on the best method of producing the blank parts.

Flame cutting, Shearing, Punching, Laser, Plasma, Water Jet and machining will prepare edges but we must consider fit up which ones can produce beveled edges where necessary and cost of each.

 Forming and Section’s: The second major consideration in fabricating is generally forming; forming parts can greatly reduce the cost of a fabrication when welds are replaced by bends at direction changes. When deg consider: Break press capacity Roll forming Making rings from tube Use breaks to bend stiffeners in large surfaces Castings where complex shapes are present

 Weld t design; As discussed weld t is selected primarily on load requirements, however variables in your design may result in startling cost overrun. Consider – t requiring the least amount of filler metal , use minimum root opening and bevel angle to accomplish this goal. On thick plate sections use double V instead of single V bevels to increase penetration and improve access for welders, specify proper reinforcement on fillet welds. The actual ts we choose fall into two distinctive groups classified as grooved welds and fillet welds, each group incorporates several variations for service requirements. Groove Welded Butt ts: The single V butt t used on plate 3/8” or lighter, requires full fusion. Strong in static tension, not well suited for bending concentrated at the root and shouldn’t be subjected to fatigue, impact loads or low temperature. A very low cost to produce.

The double V butt t is the best for all loading conditions, specified for heavy plate, penetration must be complete and alternate welding must be done in order to keep the t symmetrical. Cost is higher than a single V but less filler is ultimately required. Single U butt t readily meets ordinary load requirements; used for work with high precision fit up, used on plate ½”- ¾” thick Double U butt t for plate over ¾” or heavier must have access from both sides, costly to machine but uses less filler than the single U meets all load requirements.

Square T t Fillet welds Can be made on one side or two and light to reasonably thick materials where load subjects the weld to longitudinal shear. Care must be taken to specifying this t where severe impact or transverse loads are encountered. The Single bevel tee t withstands severe loads compared to square tee ts, confined to ½” or greater, or less where one side welding can only be done. Double bevel Tee t used where transverse and longitudinal shear are present, welded on both sides

Single J tee t used in very heavy plate where welding one side is only possible, for severe loads Double J tee t weld both sides, 11/2” and thicker, unusually severe loads

Double fillet lap t withstands more severe loads than single fillet lap ts, widely used t.

Flush corner t primarily used on 12 gauge and lighter s only moderate loads. Half open corner t used more on materials 12 gauge and up, more penetration than flush corner Full open corner t general use t where welding can be done from both sides, used on all thickness, capable of carrying heavy loads, good for fatigue and impact Edge t suitable for plate ¼” or less sustains light loads