The invention relates to a turnout rail production technology, in particular to a deeply-hardened-surface turnout rail with high degree of undercooling and the preparation method thereof. The invention aims to solve the technical problem by providing a deeply-hardened-surface turnout rail with high degree of undercooling featured in even hardness distribution and a deeply hardened surface layer and the preparation method thereof. The method is described as follows: feeding molten iron for converter smelting.fwdarw.furnace rear argon blowing station.fwdarw.LF refining.fwdarw.RH vacuumization.fwdarw.casting steel blanks.fwdarw.slow cooling in the slow cooling pit.fwdarw.austenitic homogenization.fwdarw.rail rolling.fwdarw.heat treatment; in the converter smelting process, adding 0.2-0.3% Cr, 0.04-0.06 V and 0.75-0.80% C; the heat treatment process is divided into two cooling stages. The turnout rail prepared with the method described in the invention has a deeper deeply-hardened surface layer; the hardness is distributed more evenly, the anti-contact fatigue performance is higher and the resistance to wearing is ideal.

The invention relates to a turnout rail production technology, in particular to a deeply-hardened-surface turnout rail with high degree of undercooling and the preparation method thereof. The invention aims to solve the technical problem by providing a deeply-hardened-surface turnout rail with high degree of undercooling featured in even hardness distribution and a deeply hardened surface layer and the preparation method thereof. The method is described as follows: feeding molten iron for converter smelting.fwdarw.furnace rear argon blowing station.fwdarw.LF refining.fwdarw.RH vacuumization.fwdarw.casting steel blanks.fwdarw.slow cooling in the slow cooling pit.fwdarw.austenitic homogenization.fwdarw.rail rolling.fwdarw.heat treatment; in the converter smelting process, adding 0.2-0.3% Cr, 0.04-0.06 V and 0.75-0.80% C; the heat treatment process is divided into two cooling stages. The turnout rail prepared with the method described in the invention has a deeper deeply-hardened surface layer; the hardness is distributed more evenly, the anti-contact fatigue performance is higher and the resistance to wearing is ideal.

A method for selecting a rail steel and a wheel steel comprising: selecting a rail steel and a wheel steel to be used as a rail and a wheel on an actual track, respectively, the rail steel and the wheel steel having a specific chemical composition, such that the rail comprises a head portion having a yield strength YS.sub.R of 830 MPa or more, the wheel comprises a rim portion having a yield strength YS.sub.W of 580 MPa or more, and a ratio YS.sub.R/YS.sub.W of the yield strength YS.sub.R at the head portion of the rail to the yield strength YS.sub.W at the rim portion of the wheel falls within a range of: 0.85≤YS.sub.R/YS.sub.W≤1.95 (1).

A method of producing a steel material, wherein when a cooling apparatus having a plurality of cooling sections disposed side by side in a longitudinal direction of a steel material cools the steel material hot worked or cooled/reheated, the steel material is conveyed at a conveyance distance L.sub.o (m) satisfying Equation (1), in one direction along with the longitudinal direction of the steel material, in the cooling apparatus, wherein L.sub.o is defined as conveyance distance (m) of steel material, m is a natural number, and L.sub.h is defined as length (m) of cooling sections in longitudinal direction of steel material:

(m−0.20)×L.sub.h≤L.sub.o(m+0.20)×L.sub.h  (1).

A method of producing a steel material, wherein when a cooling apparatus having a plurality of cooling sections disposed side by side in a longitudinal direction of a steel material cools the steel material hot worked or cooled/reheated, the steel material is conveyed at a conveyance distance L.sub.o (m) satisfying Equation (1), in one direction along with the longitudinal direction of the steel material, in the cooling apparatus, wherein L.sub.o is defined as conveyance distance (m) of steel material, m is a natural number, and L.sub.h is defined as length (m) of cooling sections in longitudinal direction of steel material:

(m−0.20)×L.sub.h≤L.sub.o(m+0.20)×L.sub.h  (1).

A ladder and a multipurpose ladder whose rungs and rails are made out of 7000 series aluminum alloy and which has a duty rating of at least 250 lbs. A method for producing a ladder. A method for using a ladder.

A ladder and a multipurpose ladder whose rungs and rails are made out of 7000 series aluminum alloy and which has a duty rating of at least 250 lbs. A method for producing a ladder. A method for using a ladder.

The present disclosure relates to the manufacturing of railway steel rail, and a post-weld heat treatment method for 1,300 MPa-level low-alloy heat-treated steel rail. The method comprises: (1) subjecting a steel rail welded joint having a residual temperature of 900-1,100° C. to a first stage cooling to lower the welded joint surface temperature to 650-720° C.; (2) subjecting the steel rail welded joint to a second stage cooling to lower the welded joint surface temperature to 480-550° C.; (3) subjecting the steel rail welded joint to a third stage cooling to lower the welded joint surface temperature to 10-30° C. The heat treatment takes advantage of the welding waste heat and does not require a reheating. The martensitic structure in the metallographic structure of the steel rail welded joint can be controlled to ≤1% and the fatigue life can reach 3 million times, which is conducive to operation safety of the railway.

The present disclosure relates to the manufacturing of railway steel rail, and a post-weld heat treatment method for 1,300 MPa-level low-alloy heat-treated steel rail. The method comprises: (1) subjecting a steel rail welded joint having a residual temperature of 900-1,100° C. to a first stage cooling to lower the welded joint surface temperature to 650-720° C.; (2) subjecting the steel rail welded joint to a second stage cooling to lower the welded joint surface temperature to 480-550° C.; (3) subjecting the steel rail welded joint to a third stage cooling to lower the welded joint surface temperature to 10-30° C. The heat treatment takes advantage of the welding waste heat and does not require a reheating. The martensitic structure in the metallographic structure of the steel rail welded joint can be controlled to ≤1% and the fatigue life can reach 3 million times, which is conducive to operation safety of the railway.

To provide a railway wheel which is excellent in corrosion fatigue resistance. The railway wheel according to the present embodiment has a chemical composition consisting of: in mass %, C: 0.65 to 0.80%, Si: 0.10 to 1.0%, Mn: 0.10 to 1.0%, P: not more than 0.030%, S: not more than 0.030%, Cr: 0.05 to 0.20%, Sn: 0.005 to 0.50%, Al: 0.010 to 0.050%, N: 0.0020 to 0.015%, Cu: 0 to 0.20%, Ni: 0 to 0.20%, Mo: 0 to 0.20%, V: 0 to 0.20%, Nb: 0 to 0.030%, and Ti: 0 to 0.030%, with the balance being Fe and impurities. A plate portion has a matrix structure composed of pearlite.