In a number of cases, when the product is exposed to chemical or mechanical influences, the material for its manufacture is brass with lead additive. A special lead additive to brass is produced in the manufacture of: a) wire, rod and sheet material, the high malleability of which is combined with good ability for cold processing — drilling and milling — and b) alloys for casting, for the purpose of good processing with cutting tools. In this case, brittle and short chips are usually obtained. This essay is the result of research into the extreme limits of lead content in brass according to OSTs and some special types of brass containing lead used in industry. Research (see article) has shown that α-brasses containing 67-74% copper resist cracking well if they contain from 2.5 to 3% lead. Alloys of the L60 type, containing 2.5% lead, behave somewhat worse. Brasses of the type 60-63% copper containing 1.5-1.8% lead resist cracking very poorly. Consequently, the best alloys with respect to "spontaneous cracking" are leaded α-brasses.

The phase diagrams of the aluminum-copper, aluminum-manganese, and copper-manganese systems, which bound the spatial phase diagram copper-manganese-aluminum on three sides, have been studied for a number of years by many Russian and foreign researchers and were described in some detail by Hansen as of 1936. Hansen gave a critical review of the studies he had reviewed and provided fairly complete bibliographic data. Further bibliographic data up to and including 1942 (but without any review) were published by Hotton. There are indications that in 1944 Rayner published annotations supplementing the previous works. A study of the literature of recent years has made it possible to find significant refinements to the phase diagrams of the metallic systems under consideration. The article examines the research data: 1. On the aluminum-copper phase diagram. 2. On the aluminum-manganese phase diagram. 3. On the copper-manganese phase diagram. 4. Ternary phase diagram of the copper-manganese-aluminum system (see article).

One of the most pressing problems of modern technology is lightening the weight of metal products. This problem is solved by using light, strong aluminum-based alloys and, wherever possible, replacing heavy copper, nickel and iron alloys with them. It is known from practice that two approaches have emerged for lightening the weight of products and structures. The first approach is the use of light alloys that have sufficiently high strength and corrosion resistance; the second approach is the use of heavy high-quality steels, which, due to their high strength, make it possible to manufacture products with a reduced cross-section. With the progress of modern metallurgy, it becomes clear to designers that plain carbon steel is no longer the only structural material. Alloys based on aluminum and special steels have appeared.