Here’s a DFM tip: The grain direction, particularly for anodized parts, can contribute significantly to the raw material utilization and cost for the workpiece. There are numerous technical papers on this subject that I believe would help you. [ Home ][ Forum Archive ] [ Active Engineering Forum ]. Individual grains are elongated in the direction of the metal flow or plastic deformation. Am I correct in stating that for a rectanglar bar, L = Longitudinal or actual grain direction, ST = Short Transverse = Thickness and LT = width. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework. The literature and writing on this subject is almost as expansive as the universe. The direction in which all or most of the paper fibers are oriented in a sheet or web.Since the grain is produced on the forming wire of a papermaking machine in the direction of the web's travel through the machine, the grain direction is also called the machine direction.The direction perpendicular to the grain direction is the cross-grain direction. The fatigue fracture at that time, in several cases occurred, were very clearly related to these bands. Join your peers on the Internet's largest technical engineering professional community.It's easy to join and it's free. Posted By" ">Steve on October 18, 2002 at 16:49:54:. With rectangular forgings, there are three grain directions, which describe the possibilities. They changed to a better material and better controllable heat treatment and the prpblem was solved, without any dimensional changes. Forgot one additional web site, which is probably one of the most informative on fatigue of metals; I once examined a case in which several identical high pressures pump failed through fatigue. luket (Mechanical) (OP) 9 Dec 09 12:39. The following article describes the evolution of grain size measurement and ASTM stardard E 112. A ... if yes, which properties are they - the original L or LT? The three orientations are: the long tranverse … Do you see the nerves of the wood? Production breakdowns due to seal and hose problems can cause huge losses. { The L direction is the direction the aluminum sheet is rolled, therefore the grain axis is aligned with the longest axis of this ellipsoid. Is there a test that can be done to determine grain direction of stainless 301 1/4 hard sheet? 1. The changing of rolling directions keeps the strength and elongation remaining at a high level both along RD and TD. If, for example, aluminium bends the wrong way in relation to the rolling direction, there is a risk of breakage on the metal. In such a sheet, the L direction is in the plane of the plate, and is the rolled direction (direction of longest grain axis), the LT direction is also in the plane of the sheet, perpendicular to the L direction. This eBook addresses the missing links that determine success or failure in Digital Transformation and shows how organizations can build a sustainable path forward, with fewer resources, in less time, and with better outcomes. The most common properties considered are strength, ductility, hardness, impact resistance, and fracture toughness. document.write(' ') Am I correct in stating that for a rectanglar bar, L = Longitudinal or actual grain direction, ST = Short Transverse = Thickness and LT = width. The strength of the material is going to vary based on what plate direction (i.e. offers 833 material grain direction products. (adsbygoogle = window.adsbygoogle || []).push({}); © Copyright 2000 - 2020, by Engineers Edge, LLC All rights reserved. This process has a tendency to pull the grain axis in the L direction, therefore elongating it, and squish the grain in the other two directions. if (document.getElementById("tester") != undefined) Quality is at the core of everything we do. RE: Metal Grain Direction Test? The literature and writing on this subject is almost as expansive as the universe. These grains vary in size and in orientation but are usually microscopic and their direction is determined by the processing conditions. The grain is on both sides of the sheet, and run the same direction, but there is only protective film on one side. Definition: Forging Flow Lines is a directional orientation of metal grains and any non-metallic inclusions that have been deformed due to forging. But this stretching causes the grains to spread, which manifests as cracking on the outside bend radius. Because these directions have a significant impact on the mechanical properties. Sheets of 2195 aluminum-lithium alloy were solution-treated at 507°C for 30min. Every mod you can like or share with Facebook buttons. The first letter designates the grain direction normal to the crack plane. In typical sheet or plate form, a thick billet of aluminum is squeezed or rolled through a machine that squishes the sheet out into whatever thickness desired. Aluminum plate (thickness >.250 inch) has three grain orientations, each with their own strength values. If batches of parts are being bent with some against, some with and others diagonal to the grain direction of the steel, each angle and dimension may vary across the entire batch. Promoting, selling, recruiting, coursework and thesis posting is forbidden. In metals, atoms are arranged in a crystal structure (it is not just a mess of atoms, the atoms line up in rows). In any case, the orientation of fibers tends to make the material stiffer in the direction parallel to those fibers, and more flexible and likelier to curl in the direction perpendicular to them. ; Already a member? Consider the first coupon: the load is in the L direction, the crack grows in the LT direction. Relationship of fatigue and grain direction, Mechanical engineering general discussion Forum, White Paper - Test Reuse Across MIL SIL HIL in a Development Workflow, eBook - How to Remove 5 Obstacles to Digital Transformation, White Paper - Digital Twins and Immersive Technologies in the Energy Industry, eBook - The Future of Product Development is Here. First, classically, since many metallic alloys have a very distinct grain structure and alignment, the grain structure is defined in 3 perpendicular directions: L (longitudinal), LT (long transverse) and ST (short transverse). A metal’s strength is directly related to its grain size; reducing grain size is a common way to improve material strength which often has little to no effect on the material’s toughness. Therefore, it is customary to specify specimen and crack orientations by an ordered pair of grain direction symbols. The crystalline lattice structures form during the cooling of the … By joining you are opting in to receive e-mail. In aluminum alloys, it is often very easy to see which direction is which by looking at cut metal under a powerful optical microscope. The grains run parallel to the rolling direction. Subject: Re: Grain Direction. If anything, the ST direction axis is usually shorter than the LT direction axis. In the CAD shop, the Base Flange (as designated in most 3-D CAD modeling packages) makes the … Please let us know here why this post is inappropriate. Looking to make the design and manufacturing of your products more agile? Mechanical properties are also used to help classify and identify material. So let me try to formulate an answer in a different way. Thank you for helping keep Eng-Tips Forums free from inappropriate posts.The Eng-Tips staff will check this out and take appropriate action. < "> Speaking for aluminum alloys alone, think of the grain as being generally shaped like an ellipsoid, with one axis very long relative to the others, and the two other axes almost equal in dimension. All pumps (about 4 as far as i can remember) had the same structure. L, LT, & ST G, 10. The software determines the smallest rectangle (bounding box) that aligns with the grain direction to fit the flat pattern. CoryPad (Materials) 11 Dec 09 19:57. If you want to specify the rolling direction on the sawn material, in the example below it will be 300 mm. The changing of rolling directions can refine the grains. The material at the time had a distinc banded structure due to some structural inhomogenity. In this white paper learn how a standards-based, systematic, and automated generative MDD/XIL workflow helps automotive engineers develop their production ECU Verification & Validation (V&V) suites early during software modeling, and reuse them throughout the overall systems engineering project. Login. In contrast to the straight grain, you can also design garments which use the grain on a 45-degree angle, this is called bias cut. else It was written by George Vander Voort on the occasion of the 75 th anniversary of Committee E-4 on metallography and originally appeared in ASTM Standardization News, May, 1991 as "Committee E-4 and Grain Size Measurements: 75 years of progress. IT has been generally accepted for some time that the mechanical properties of light alloys varied with the direction of grain, but even in the design of aircraft structures only a slight allowance has been made for this variation. Imagine, you’ve got a piece of wood. Registration on or use of this site constitutes acceptance of our Privacy Policy. K(IC) in S-L Direction: Fracture Toughness: 31 MPa-m½: 28.2 ksi-in½ K(IC) in T-L Direction: Fracture Toughness: 35 MPa-m½: 31.9 ksi-in½ K(IC) in L-T Direction: Shear Modulus: 26.9 GPa: 3900 ksi : Shear Strength: 303 MPa: 44000 psi AA; Typical: Electrical Properties In this white paper, you will learn how real-time 3D technology can enable this optimization at all stages within the energy industry. The rolling directions affect the microstructure and texture of Mg-5Li-1Al-0.5Y alloy, thus making influences on the mechanical properties of the alloy. Most structural materials are anisotropic, which means that their material properties vary with orientation. The Forging Industry recognizes "L" sometimes described as "LG" or longitudinal, LT, long transverse and ST, short transverse grain directions. Therefore, we make every effort to deliver high quality products that meet your needs. Now think about two compact tension specimens, the ASTM standard. Our materials are certified to 3-A Standard 18-03, FDA CFR 21.177 and USP Cl VI. Optimising material utilisation in nest layouts is vital when parts are remaining flat. More importantly, non-metallic inclusions, particles and other impurities inherited during the casting process are elongated in the direction of grain flow. If the material is to be hemmed, the protective film will be on the outside, unless it is specified to be different. The bias grain of a piece of woven fabric, usually referred to simply as "the bias", is any grain that falls between the straight and cross grains.When the grain is at 45 degrees to its warp and weft threads it is referred to as "true bias." Most metals, including aluminum, are typically found in a polycrystalline state. Grain orientation and loading direction per ASTM B769 b. The axis dimension in the two other directions, LT and ST, is much shorter than the L direction. The fracture toughness of a material commonly varies with grain direction. A wide variety of material grain direction options are available to you, such as dining room furniture, uv gel. Example of rolling direction indications on sawn material. 3. ksi: ... Metallic Materials . // --> I am trying to explain grain direction and need a picture of L, LT & ST to define. Am I correct in stating that for a rectanglar bar, L = Longitudinal or actual grain direction, ST = Short Transverse = Thickness and LT = width. Every piece of woven fabric has two biases, perpendicular to each other. Grain Direction Is Important. LT Direction: This is the orthogonal ‘Long Transverse’ (LT) grain direction in the plane of the plate, shown in red above; ST Direction: Finally we have the ‘Short Transverse’ (ST) grain direction, the weakest grain direction shown in green above; So why did we first discuss the grain directions? As applied to cloth, the term refers to the way the fibers are woven. Texture or grain direction must be taken into account for accurate predictions of material behavior and characteristics when forming/bending. FS19 mods - website where you will find a lot of mods of Farming Simulator 19 mods. Close this window and log in. All mods you can download for free. Base Flange Versus Sheet Stock. So, from time to time we need to show the direction of the grain on sheet metal parts. document.write(''); I recall it propagates fastest in when you load the coupon in the ST direction, but since there is so little data there (given the difficulty in obtaining coupons in loading such a coupon except when the plate is very thick), I can't say for certain. In addition to the new "bounding box" sketch, there is a new option in the property manager for the Flat-Pattern feature: "Grain Direction".You can define a grain direction to use when calculating the bounding box for sheet metal parts. TVP - I just realized ... Metal Grain Direction Test? 2. }. You’re getting answers that describe electric fields, however you ask about materials. Although not as visible, grains in a piece of steel are like the wood grain in a piece of lumber. Is there any relationship of fatigue crack growth to material grain direction?