Abstract: A titanium alloy is prepared containing 2 to 4% by weight of aluminum, 1.5 to 2.5% by weight of vanadium, 0.20 to 0.45% by weight of a rare earth element (not essential). 0.05 to 0.11% by weight of sulfur (not essential), and titanium substantially for the remainder, the ratio of the rear earth element content to the sulfur content ranging from 3.8 to 4.2. This titanium alloy is rough-formed and hot-forged at a temperature in a .beta. region, and the resulting titanium alloy ingot is processed directly into a titanium alloy component having a desired shape. The titanium alloy component thus manufactured has a satisfactory fatigue strength and is also excellent in machinability, and can be used for connecting rods, valves, retainers, etc. to be incorporated in the engine of an automobile.

Abstract: An austenitic stainless steel having improved free cutting properties is disclosed, which consists essentially of, on a weight ratio, C.ltoreq.0.2%. Si.ltoreq.2.0%, Mn.ltoreq.2.0%, 7.5%.ltoreq.Cr.ltoreq.30.0%, Ni.ltoreq.40.0%, 0.005%.ltoreq.Bi.ltoreq.0.50%, 0.0003%.ltoreq.B.ltoreq.0.10%, 0.002%.ltoreq.S.ltoreq.0.40%, P.ltoreq.0.02%, N.ltoreq.0.05% and/or O.ltoreq.0.005% and the balance being Fe.

Abstract: A free-cutting Ti alloy is disclosed. The basic alloy composition of this free-cutting Ti alloy essentially consists of at least one of S: 0.001-10%, Se: 0.001-10% and Te: 0.001-10%; REM: 0.01-10%; and one or both of Ca: 0.001-10% and B: 0.005-5%; and the balance substantially Ti. The Ti alloy includes one or more of Ti-S (Se, Te) compounds, Ca-S (Se, Te) compounds, REM-S (Se, Te) compounds and their complex compounds as inclusions to improve machinability. Some optional elements can be added to above basic composition.Also disclosed are methods of producing the above free-cutting Ti alloy and a specific Ti alloy which is a particularly suitable material for connecting rods.

Abstract: Sulfur-containing free-cutting steel may have an improved machinability and fewer defects by adding certain amounts of Te, Pb and Bi to prevent elongation of sulfide inclusion particles, and by lowering Al-content to decrease Al.sub.2 O.sub.3 of oxide inclusions or by lowering O-content to decrease large Al.sub.2 O.sub.3 inclusion particles. The free-cutting steel may be produced by continuous casting.

Abstract: Mechanical anisotropy of a free cutting steel having excellent machinability can be effectively decreased by controlling inclusions so that the steel may contain inclusion A which softens at a temperature below 1000.degree. C. and inclusion B which has a melting point above 1300.degree. C. but exhibits plasticity at a temperature between 900.degree. and 1300.degree. C., that the inclusion A and the inclusion B may exist in a mutually adhered form, and that the areal percentage of the inclusion A may be at least 1% of areal percentage of the inclusion B.Typical compositions of the inclusion A are: Pb, Bi, MnS--MnTe, SiO.sub.2 --K.sub.2 O, SiO.sub.2 --Na.sub.2 O, SiO.sub.2 --K.sub.2 O--Al.sub.2 O.sub.3, SiO.sub.2 --Na.sub.2 O--Al.sub.2 O.sub.3 and SiO.sub.2 --Na.sub.2 O--CaO--MnO; and typical compositions of the inclusion B are: MnS, MnSe and Mn(S,Se).

Abstract: A steel for cold forging containing C up to 0.6%, Si up to 0.5%, Mn up to 2.0%, S 0.003 to 0.04% and Te up to 0.03%, wherein ratio %Te/%S being at least 0.04, and further, Al up to 0.04%, N up to 0.02% and O up to 0.0030%, and the balance being substantially Fe exhibits both good formability in cold forging and good machinability.The steel may further contain one or more of additional alloying elements selected from the group of Ni, Cr and Mo, the group of V, Nb, Ti, B and Zr, and the group of Pb, Se, Bi and Ca.The steel for cold forging having good machinability is made preferably by agitating molten steel containing adjusted amounts of the alloying elements other than Te, and, if used, members of the Pb group, by introducing non-oxidizing gas thereinto so as to float up and separate large sized particles of non-metallic inclusions, and subsequently adding predetermined amount of Te and other elements.

Abstract: A free cutting steel for machine structural use containing C up to 0.6%, Si up to 2.0%, Mn up to 2.0%, S 0.04 to 0.4%, Te 0.002 to 0.5% and O 0.0010 0.0300%, the balance being substantially Fe exhibits excellent machinability when the MnS-based inclusion is in the form of particles of 5 to 100.mu. long, 1 to 10.mu. wide, wherein the aspect ratio length/width is not larger than 10, and at the density of 20 to 200 particles per 1 mm.sup.2 of the matrix cross section.A free cutting steel for machine structural use containing C up to 0.6%, Si up to 2.0%, Mn up to 2.0%, S 0.04 to 0.4% and Te up to 0.1%, wherein %Te/%S is at least 0.04, O up to 0.003% and N up to 0.0200%, the balance being substantially Fe exhibits improved rolling-contact fatique strength when at least 80% of sulfide-based inclusion particles of 10.mu. long or more have the aspect ratio length/width of 5 or less, and when areal percentage of alumina cluster in the matrix cross section is not higher than 0.5%.

Abstract: The present invention relates to a free-cutting structural steel for machines characterized by containing a range of 30-100 g/steel ton of oxide inclusions mainly composed of SiO.sub.2 40-60%, CaO 13-30% and Al.sub.2 O.sub.3 25-40%, the balance being less than 20% of other oxides and calcium 0.0002-0.0010%, and at least one of the following elements; lead 0.03-0.30% and sulfur 0.035-0.10%.