Because of extreme difficulties encountered in forging some compositions, wrought standard samples will not be available initially for a few standards. For example, the high impurity level standard of both cartridge brass, NBS No. 1100, and red brass, NBS No. 1109, would not permit forging without severe cracking. Additionally, the low lead composition standard (2% nominal) of the free-cutting brass series, NBS No. 1105, and all three of the aluminum brass series, Although the standards described above would not forge, it was believed that an extrusion process could be utilized to produce the wrought samples. In late 1961, test lots of the red brass, NBS No. 1109, and the free-cutting brass, NBS No. 1105, were sent to Nuclear Metals, Inc. for extrusion by a procedure agreed upon by both NBS and NMI. Subsequent testing of selected extruded samples indicated that the material should be satisfactory for the wrought samples although some cracking and some nonuniformity of metallurgical structure was in evidence. Based on the above investigation, the remaining material of all the standards that would not forge (with the exception of the one for cartridge brass which broke up completely on forging and could not be extruded) were sent to NMI for extruSome of the pertinent details of the procedure follow: the NBS copper-base material was cut into convenient size pieces for close packing in copper extrusion cans (about sion. (a) 6-in. diameter); (b) each cut piece was given a light etch (<5 seconds) in dilute nitric acid before packing in the cans; (c) the cans were evacuated to 0.03μ pressure at room temperature and sealed; (d) the extrusion temperature was 1550°F, the ram speed 40 in./min, and the extrusion force from about 700-950 tons; (e) the final extruded size was 1 1/2 in. in diameter. As with the test lots, some cracking and nonuniformity of metallurgical structure was evident on testing the returned material. Although all the testing has not been completed at this writing, it is believed that the material will be useful as wrought standard samples. A separate report covering the testing of the extruded material has been planned. 10. CHEMICAL ANALYSIS Samples for cooperative chemical analysis were prepared in the form of millings taken from the cross section of the finished samples of both the chill-cast and wrought material. Chemical analyses were made at NBS for all standards and in six cooperating laboratories, one of which also analyzed all standards.* * Quantitative Separations Section (formerly Standard Reference Materials Section), National Bureau of Standards, Washington, D.C. (R. K. Bell and E. E. Maczkowske). Analyzed all standards. Department of Mines and Technical Surveys, Mines Branch, Ottawa, Ontario, Canada (A. E. La Rochelle, Elsie M. Penner, C. H. McMaster, and W. R. Inman). Analyzed all standards. Provisional Certificates of Analyses were prepared for naval brass in March, 1961 (revised in August 1962); for cartridge and red brass in August 1962; and for free-cutting brass, gilding metal, commercial bronze, and aluminum brass in February, 1964. The certified values are shown in table 4**. It is to be noted that additional elements having useful concentration ranges are contained in the cartridge brass series to include Al, Sb, As, Be, Bi, Cd, Ag, and Te. *(Footnote con't from preceding page) Anaconda American Brass Co., Waterbury, Conn. (0. P. Case and Mrs. Kathleen M. O'Brien). Analyzed cartridge, naval, and red brass. Anaconda American Brass Co., Metallurgical Dept., Research and Technical Center, Waterbury, Conn. (Joseph P. Irwin). Analyzed commercial bronze and aluminum brass. Revere Copper and Brass, Inc., Rome, N.Y., (Frederick V. Schatz and R. E. Hahn). Analyzed free-cutting brass, gilding metal, commercial bronze and aluminum brass. Mueller Brass Co., Port Huron, Mich. (S. C. Richards, Ray Stevens and Albert Stuever). Analyzed cartridge, naval, and red brass. Twin City Testing and Engineering Laboratory, Inc., St. Paul, Minn. (Albert C. Holler). Analyzed free-cutting brass. Ledoux and Co., Teaneck, N. J. (Silve Kallmann). Analyzed gilding metal. ** A brief summary of the chemical methods used in the analysis of the copper-base alloys is available on request to the Analytical Chemistry Division, National Bureau of Standards, Washington, D.C. Additionally, a paper is being prepared describing the factors involved in the basic standardization of the x-ray spectrochemical method as applied to the certification of the copper-base alloys. This paper will appear shortly in this publication series. |