ASTM C974-87(R2020) pdf free download

ASTM C974-87(R2020) pdf free download.Standard Practice for Preparing Test Specimens from Basic Refractory Castable Products by Casting
1. Scope
1.1 This practice covers a procedure for preparing test specimens from a basic refractory castable by casting prepared material in a mold. Specimens prepared in accordance with this procedure are intended for use in ASTM test methods. 1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.4 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Significance and Use
2.1 This practice defines a procedure that ensures consistent preparation of specimens for product testing and evaluation. 2.2 This practice can be used in the laboratories of producers, users, and general-interest parties for research and development or quality-control work. It is particularly useful for interlaboratory comparisons or products, for repetitive evaluations or comparisons of products or product quality, and in specifying a uniform preparation practice for specimens for acceptance testing. 2.3 In using this practice it must be recognized that the structure of laboratory-cast specimens may differ significantly from the structure of material cast in field applications.
3. Apparatus
3.1 Mixer, bench-type, Hobart or equivalent. 3.2 Steel Molds. 3.3 Vibration Table, spring or air-cushioned, with a pneu- matic or electric driver. 2 3.4 Oven, air circulating.
4. Procedure
4.1 Store the material to be tested at 85 6 2 °F (29.5 6 1 °C) for 24 h prior to testing. 4.2 Reduce the sample to the desired batch size with a sample splitter or by quartering, taking precautions to prevent segregation. Sufficient material should be batched to provide at least a 10 % excess over test specimen requirements. 4.3 Add the weighed, dry batch to the mixer and dry-mix at low speed for 30 s. Continue to mix at low speed while adding the required amount of water (see 4.3.1) within 30 s. Wet-mix at low speed for 4 min. 4.3.1 Use the amount of water and mixing time (if different from above) recommended by the manufacturer. The water must be potable and at a temperature of 85 6 2 °F (29.5 6 1 °C). Measure the water addition to the nearest 0.1 % by weight. 4.4 Specimens should be cast in a mold immediately after the batch is mixed so that all specimens made from a batch are cast at the same time. The mold should be securely clamped to the vibration table top. Fill the mold to overflowing, distribut- ing the material uniformly between each cavity. Vibrate in accordance with the manufacturer’s instructions. Approxi- mately 15 s before the end of the vibration period, remove excess material (approximately flush with top of mold). 4.4.1 If the batch is too wet, water will run off the specimens, while ifthe batch is too dry, the material will not fill the mold. In either case, the batch must be discarded and another run made at a suitable water content. 4.5 Test specimens should be air-dried in the molds a minimum of 16 h and a maximum of 24 h, and then removed from the molds and dried for a minimum of 8 h at 225 6 5 °F (107 6 2.5 °C) in a circulating air dryer prior to testing.