A connecting rod for a variable compression internal combustion engine, the connecting rod including a crank bearing eye for connecting the connecting rod with a crank shaft; a connecting rod bearing eye configured to connect the connecting rod with a cylinder piston of the internal combustion; an eccentrical element adjustment arrangement configured to adjust an effective connecting rod length, wherein the eccentrical element adjustment arrangement includes an eccentrical element that cooperates with an eccentrical element lever, wherein the eccentrical element is configured to receive a wrist pin of the cylinder piston, wherein the eccentrical element adjustment arrangement includes at least one cylinder with a piston that is displaceably supported in a cylinder bore hole and connected with a support rod, wherein the eccentrical element lever includes two eccentrical element lever segments which are connected by at least one connecting bolt to which the support rod is pivotably connected.

The present invention relates to a ferritic stainless steel according to the present invention, containing, in mass %: 0.001%C0.020%, 0.05%Si0.50%, 0.1%Mn1.0%, 15.0%Cr25.0%, Mo<0.50%, 0.50%W5.00%, and 0.01%Nb0.50%, with a balance being Fe and unavoidable impurities, having a content (coarse Laves phase ratio) of coarse Laves phase having a diameter of 0.50 m or more being 0.1% or less, and having an average grain size being 30 m or more and 200 m or less.

A bolt is provided that has high strength and excellent hydrogen embrittlement resistance characteristics. A bolt according to an embodiment of the present invention consists of, in mass %, C: 0.32 to 0.39%, Si: 0.15% or less, Mn: 0.40 to 0.65%, P: 0.020% or less, S: 0.020% or less, Cr: 0.85 to 1.25%, Al: 0.005 to 0.060%, Ti: 0.010 to 0.050%, B: 0.0010 to 0.0030%, N: 0.0015 to 0.0080%, O: 0.0015% or less, Mo: 0 to 0.05%, V: 0 to 0.05%, Cu: 0 to 0.50%, Ni: 0 to 0.30%, and Nb: 0 to 0.05%, with the balance being Fe and impurities. The bolt satisfies Formula (1) and Formula (2), and has a tensile strength of 1000 to 1300 MPa and satisfies Formula (3).
4.910C+Si+2Mn+Cr+4Mo+5V6.1(1)
Mn/Cr0.55(2)
[dissolved Cr]/Cr0.70(3)

A high-strength screw (1) includes a head (2) and a threaded portion (5) including a thread (6) and a thread end (9) facing away from the head (2) in an axial direction. The threaded portion (5) includes an unhardened portion (12) starting at the thread end (9) and extending in an axial direction. The unhardened portion (12) has a hardness being reduced compared to an axial middle portion (11) of the threaded portion (5).

A high-strength screw (2) includes a threaded portion (7) having a thread (8). The screw (2) includes an inner core (16) as seen in cross-section of the screw (2), the core (16) having a first hardness. The screw (2) includes an outer surface layer (17) as seen in cross-section of the screw (2). The screw (2) includes an unhardening layer (18) forming the outer surface layer (17) in the threaded portion (7), the unhardening layer (18) having a second hardness being reduced compared to the first hardness of the core (16).

A steel comprising 0.07 to 0.14 wt. % of carbon, 13 to 15 wt. % of chromium, 1.3 to 1.7 wt. % of molybdenum, 1.5 to 2.0 wt. % of nickel and 1.0 to 1.5 wt. % of manganese and use of the steel for producing screws is provided.

Disclosed are wire rods and parts with improved delayed fracture resistance, and methods for manufacturing the same. The wire rod with improved delayed fracture resistance according to the present disclosure contains, by wt %, 0.15-0.30% of C, 0.15-0.25% of Si, 0.95-1.35% of Mn, 0.030% or less of P, 0.030% or less of S, 0.015-0.030% of Ti, 0.0010-0.0040% of B, 0.0010-0.0080% of N, and Fe and inevitable impurities as the balance, and satisfies formula 1 of 2.05.5[Si]+[Mn]2.4, where [Si] and [Mn] represent the contents (wt %) of the corresponding elements.

A high-strength bolt is provided that has high strength and excellent hydrogen embrittlement resistance characteristics. A bolt according to this invention has a chemical composition consisting of, in mass %, C: 0.22 to 0.40%, Si: 0.10 to 1.50%, Mn: 0.20 to less than 0.40%, P: 0.020% or less, S: 0.020% or less, Cr: 0.70 to 1.45%, Al: 0.005 to 0.060%, Ti: 0.010 to 0.045%, B: 0.0003 to 0.0040%, N: 0.0015 to 0.0080% and O: 0.0020% or less, with a balance being Fe and impurities, and satisfying Formula (1) and Formula (2), and with the high-strength bolt having a tensile strength of 1000 to 1300 MPa.
0.50C+Si/10+Mn/5+5Cr/220.85(1)
Si/Mn>1.0(2) Where, a content (mass %) of a corresponding element is substituted for each symbol of an element in Formula (1) and Formula (2).

The present invention relates to a high-hardenability, medium-carbon, low-alloy round steel for fasteners, the chemical constituents by mass percentage are as follows: C: 0.360.44%, Si: 0.150.40%, Mn: 0.801.00%, Cr: 1.001.15%, Mo: 0.050.25%, Ni: 0.050.25%, Cu: 0.050.25%, Al: 0.0150.050%, B: 0.00100.0050%, Ti: 0.0200.050%, the balance is Fe; the maximum diameter of the round steel is 65 mm. The manufacturing process are as follows: the raw materials are processed, in sequence, by converter smelting, LF refining, RH/VD degassing to obtain molten steel, feeding Ti wires and ferroboron, continuous casting, rolling into the bar, obtaining the quenched and tempered round steel after quenching and tempering treatment; the quenched and tempered round steel is able to be directly used in processing fasteners which meet ISO 898-1 standard for grade 10.9, such as bolts and the like.

A hollow screw and related process of making is provided, wherein the hollow screw is formed from a generally circular corrosion resistant stainless steel disk cut from flat roll stock. The hollow screw includes a head and an elongated and hollow shaft having a wall thickness between about 0.2 to about 0.7 millimeters extending therefrom and defining a shank portion and a threaded portion having a plurality of threads thereon with a rotational drive mechanism configured to facilitate tightening via the threads. The process involves annealing to soften the stamped hollow screw, followed by thread rolling, and then age hardening the hollow screw. As such, the resultant hollow screw is relatively lightweight, about 50% the mass of a solid core screw made from the same material, with a sufficient thread strength to meet most aerospace applications and contributes to important aircraft fuel economy.