Abstract: The present invention provides a steel wire rod having a lubricating coating film, which can achieve both workabilities such as wire drawability, spike property and ball ironing property, and corrosion resistance such as long-term rust prevention property; and a method for producing the same. Disclosed are a steel wire rod having a coating film containing no phosphorus, wherein the coating film includes a lower layer coating film composed of oxide and/or hydroxide of zirconium and having a film thickness of 1.0 to 200 nm, and an upper layer coating film containing silicon and tungsten, in order from a steel wire rod side, a mass ratio of tungsten/silicon being in a range of 1.3 to 18; and a method for producing the above steel wire rod, which includes bringing an aqueous chemical conversion treatment solution, which has a pH in a range of 2.5 to 5.0 and contains a water-soluble zirconium compound dissolved therein, into contact with a surface of a steel wire rod to form a lower layer coating film.

Abstract: The present invention provides a steel wire rod including a lubricating coating film, which can reconcile workabilities such as wire drawability, spike property, ball ironing property and film removability, and corrosion resistance such as long-term rust prevention property. The steel wire rod includes a lubricating coating film on a surface, wherein the lubricating coating film contains a water-soluble silicate and a water-soluble tungstate, a mass ratio of water-soluble tungstate/water-soluble silicate being in a range of 0.

Abstract: Provided is a water-soluble rubricating agent for plastic working being capable of forming a lubricating film having lubricity and seizure resistance equal to or greater than a phosphorus-containing chemical conversion treatment film, having excellent corrosion resistance, and also having good film adhesion, without including phosphorus in the film. This water-soluble non-phosphorus lubricating agent for plastic working includes an inorganic solid lubricant as component A, a wax as component B, and a water-soluble inorganic metal salt as component C, wherein the mass ratio (component A/component B) of solid content for component A to solid content for component B is 0.1 to 5, and the mass percentage (component C/(component A+component B+component C)) of solid content for component C to total solid content for components A, B and C is 1 to 30%.

Abstract: Provided is a water-soluble rubricating agent for plastic working being capable of forming a lubricating film having lubricity and seizure resistance equal to or greater than a phosphorus-containing chemical conversion treatment film, having excellent corrosion resistance, and also having good film adhesion, without including phosphorus in the film. This water-soluble non-phosphorus lubricating agent for plastic working includes an inorganic solid lubricant as component A, a wax as component B, and a water-soluble inorganic metal salt as component C, wherein the mass ratio (component A/component B) of solid content for component A to solid content for component B is 0.1 to 5, and the mass percentage (component C/(component A+component B+component C)) of solid content for component C to total solid content for components A, B and C is 1 to 30%.

Abstract: The present invention provides a steel for a fracture splitting type connecting rod, in which: the steel contains C: 0.25-0.5% (in mass %, the same is applied hereunder), Si: 0.01-2.0%, Mn: 0.50-2.0%, P: 0.015-0.080%, S: 0.01-0.2%, V: 0.02-0.20%, Cr: 0.05-1.0%, Ti: 0.01-0.10%, and N: 0.01% or less; an f-value represented by the expression shown below is in the range of 0.003 to 0.04; and the average aspect ratio of sulfide system inclusions is 15 or less, f=[Ti]?[N]×48/14 (in the expression, [Ti] and [N] represent the contents (mass %) of Ti and N in a steel, respectively).

Abstract: The present invention provides a rolled material having excellent fracture splitting characteristics and suitable for the manufacture of a connecting rod in which a through-hole section for assembly in a crankshaft is fracture split in substantially semicircles. Prescribed components are contained, an average aspect ratio of a sulfide-based inclusion as observed in a D/4 portion (D is the diameter of the rolled material) in a cross-section parallel to a longitudinal direction of the rod-shaped rolled material is not more than 10.0, a Pc indicated in Equation (1) below is between 0.41 and 0.75, and a Veq indicated in Equation (2) below is not less than 0.18 mass % Pc=C(1??/100)??(1) {In Equation (1), C represents the carbon content in steel (mass %) and ? represents the ferrite fraction (area ratio %)} Veq=V+Ti/2+Si/20??(2) {In Equation (2), V, Ti and Si represent the content of each element in steel (mass %)}.