Structure news. Product News from Struers. In this issue. TransPol-5

Transcription

1 1 Structure # 10 April 2011 Product News from Struers TransPol-5 TransPol-5 is a portable, metallographic grinding/ polishing machine. An exchangeable battery pack offers up to 1½ hours of continous battery operation. All necessary accessories are included, and are easily stored in the hold of the carrying case. Here, there is also plenty of storage space for all consumables needed for the preparation. In this issue New TransPol-5 1 New DuraVision 2 Application case 3-4 Courses and Events 5 Structure is a quarterly letter from Struers, the world leader in materialography. The letter provides you with up-to-date information on materialography, applications and new innovative products. For more information about our products, please contact your local sales representative, listed on TransPol-5 comes with a 3 m cable. When the operator needs to climb onto e.g. a ladder, the carrying case can stay on the ground, while the grinding/polishing unit is remote-controlled from the elevated position. The portable grinder/polisher comes with both an angled and a straight handle, and exchangeable rubber discs, upon which the grinding paper and polishing cloth are mounted. To subscribe to Structure, please go to our website; Read more at

2 New products # 10 April New products Struers covers the entire range of equipment and consumables for materialographic specimen preparation - from uncomplicated manual machines to sophisticated computerized preparation solutions. Struers is constantly working on improving existing and developing new products. DuraVision - New macro hardness testers The new innovative load-cell based DuraVision offers extremely fast and fully automatic hardness testing of Brinell, Vickers and Rockwell. Available with test load ranges from kgf or kgf, the DuraVision covers the full spectrum of regular hardness testing. The unique ecos Workflow software lets you follow the natural flow in hardness testing. The simplicity and ease of use will enable you to perform high quality hardness testing comfortably and with a minimum of training required. Read more at The entire test cycle of load application, indentation, focusing, illumination adjustment and hardness evaluation is now carried out fully automatically without touching the machine hereby ensuring 100% repeatability in testing. Automatic illumination adjustment Load cell technology Motorized test head Touch screen operated Optical system 6-position automatic turret Easy and flexible clamping Fixed and sturdy test anvil DuraVision-20-/30 DuraVision-200-/300

3 Application # 10 April Application Struers application knowledge represents a cornerstone in our daily work - wherever it is, inside or outside the company. We offer a wide range of tools to share our knowledge, from on-line courses to group courses and seminars. Cutting of steel rod with a surrounding glass layer containing steel threads Introduction Very brittle materials are prone to cracking during the cutting process due to the forces applied. We received a specific case where the customer experienced problems with cracking of the surrounding glass layer on a steel rod, when trying to make a cross-section. The customer wanted to examine the dimensions of the steel threads and the glass layer. The customer attempted to cut his specimen using a technique with the specimen fixed, and canola oil as cutting fluid. The result was that the end part of the glass layer, not supported by the steel core, cracked due to the forces applied. The customer s argument for using the canola oil was to minimize friction between the cut-off wheel and the specimen. Attempts / trials Several unsuccessful attempts were made to cut the rod satisfactorily by using a precision cut-off machine. 1. First, a technique with the specimen fixed was used with a very low feed speed (0.01 mm/s), using water as cutting fluid, in order to minimize the force applied on the brittle glass layer. However, this was not sufficient and cracking of the glass could not be avoided, even though the lower feed speed helped reducing the cracking slightly. 2. Then, the same parameters were used, but with an oil-based cutting fluid, without any visible differences in the quality of the cut. Thus, we decided to make the remaining cuts using water as cutting fluid, also to minimize the need for cleaning after the cutting process. Figure 1: Various trial results 4. Then we tried to decrease the cut-off wheel speed, thus lowering the force applied to the specimen. Care had to be taken not to destabilize the cut-off wheel (high wheel speed helps to stabilize the thin wheels). The largest possible flange was used to provide as much support to the cut-off wheel as possible. But once again the glass layer cracked. The conclusion was that, in order to avoid cracking completely, the glass needed to be supported perpendicularly to the cutting direction. 5. To achieve this, we decided to mount the specimen in RepliFix-2 (a fast curing silicone rubber) before cutting, which resulted in only minor cracks, but still left a burr due to the sample breaking apart before being cut through. 3. Various cut-off-wheels were tried, and it was established that the thin cut-off-wheels created less damage to the glass layer than the thicker ones; a metal bonded diamond cut-off wheel (M1D08) gave the best result. As it was not possible to avoid cracking of the glass when using a method where the specimen was fixed, even when the glass was supported, this method was abandoned. Instead we attempted to cut the specimen with a method where the

4 Application # 10 April specimen was rotated during the cutting process. Workpiece rotation reduces the contact area between the cut-off wheel and the workpiece to a minimum. The advantage of this technique being that the steel core of the rod supports the glass layer until it is cut through. This method had a disadvantage though, as it was not possible to clamp the entire specimen securely because of the limited space when the setup for rotating the specimen was used. To compensate for this, an initial cut to acquire a smaller section was made, which could be clamped securely when using the rotating specimen technique. The smaller section was cut from the rod using the fixed specimen technique, the rod was mounted beforehand in RepliFix-2 to minimize cracking. Then the small section was clamped in a sample holder suitable for a rotating specimen. The process with the rotating specimen, similarly to the fixed specimen process, took place at a very low feed speed to minimize the risk of cracking of the glass, as well as a low wheel speed to reduce the forces applied to the glass. This method resulted in a cut with no visible cracks and no burrs in the glass. The optimal cutting method was found! Figure 2: Three-jaw chuck for centering and clamping of cylindrical specimens. The chuck is placed in a rotary stand on a precision cutoff machine. The only burr left was a tiny needle in the centre of the specimen. This burr is left because the sample will break apart when the needle cannot carry the weight of the free hanging part of the specimen anymore. Conclusion By using the technique where the specimen is rotated, the need for further preparation is minimized because the burr in the centre of the specimen will not hinder an examination of the glass layer and steel threads. Figure 3: The final cut, without cracks in the glass layer. Cut Wheel Flange Cut type Feed speed Wheel speed Initial* M1D10 50 mm Fixed specimen 0.01 mm/s 2500 rpm Final M1D08 50 mm Rotating specimen 0.01 mm/s 2500 rpm *Mounted in RepliFix-2, which allowed the use of a slightly larger cut-off wheel to ensure that the rod was entirely cut through.

5 Courses and Events # 10 April Courses and Events Struers is the world leader within materialography and possess the greatest experience in this line of business with regard to equipment, consumables and preparation know-how in connection with quality control, research and failure analysis. Materialographic Events around the world 2011 United States Non-Destructive Testing and Field Metallography Web Event 2PM EDT, 28/04 Germany, Stuttgart Messe Control, Halle 3, Stand /05-06/05 Hungary, Budapest Seminar on Efficient Specimen Preparation 04/05 UK, Rotherham The Professional Materialographer 10/05-12/05 Austria, Wien Workshop 11/05 United States Non-Destructive Testing and Field Metallography Web Event 2PM EDT, 12/05 Finland, Helsinki, The Professional Materialographer 17/05-19/05 Netherlands, locatie Willich DE Cursus Materialografie door Struers Nederland 21/06-22/06 Turkey, Istanbul The Professional Materialographer 23/05-25/05 Denmark, Ballerup The Professional Materialographer II 24/05-25/05 Austria, Leoben Materialografiekurs 24/05-26/05 United States Non-Destructive Testing and Field Metallography Web Event 2PM EDT, 26/05 Turkey, Izmir Seminar on Efficient Specimen Preparation 27/05 China, Shanghai The Professional Materialographer 07/06-09/06 Germany, Ottensoos Praxisseminar Bildanalyse 08/06-09/06 UK, Rotherham The Professional Materialographer 14/06-16/06 Switzerland, Baden Workshop 22/06 China, Shanghai Control China, Intex Shanghai, Stand 1D28 23/08-25/08 Denmark, Ballerup The Professional Materialographer Extended 12/09-15/09 Singapore, Singapore The Professional Materialographer 12/09-15/09 Germany, Karlsruhe Metallografie-Tagung 14/09-16/09 Poland, Kielce Fair Control-Tech 28/09-30/09 Germany, Aalen Materialografiekurs 28/09-30/09 Czech Republic, Brno Fair MSV 03/10-06/10 Germany, Wiesbaden Härtereikolloquium 12/10-14/10 Germany, Ottensoos Materialografiekurs 08/11-10/11 Denmark, Ballerup The Professional Materialographer Extended 14/11-17/11 Keep yourself updated on upcoming courses and events on Copyright 2011 Struers A/S. All Rights Reserved.