Single-tooth track plate cogging-down pass and hot rolling method

A hot rolling method for single-tooth track plate, utilizing a single-tooth track plate cogging-down pass, wherein the method includes the following steps of:

• step 1) using a cogging mill to cog down a rectangular continuous casting billet, the continuous casting billet are rolled sequentially by 1 to 4 first cogging holes, and the continuous casting billet is gradually rolled out into a right bent limb, a first center column, and a left bent limb of the first cogging holes, the first cogging holes comprising a first inclined plane, a second inclined plane, a third inclined plane, a fourth inclined plane, a fifth inclined plane, a sixth inclined plane, and a first plane, a second plane, a third plane and a fourth plane;
• wherein, the first inclined plane and the first plane cooperate with the fifth inclined plane and the fourth plane to form the right bent limb, the second inclined plane, the second plane and the third inclined plane cooperate with the fourth plane to form the first center column, the third plane and the fourth inclined plane cooperate with the fourth plane and the sixth inclined plane to form the left bent limb, and a cross-section of the continuous casting billet changes from a rectangle to a mountain shape, thus obtaining a mountain shaped middle billet, the mountain shape is a shape having three mountain peaks, wherein a rightmost peak corresponds to the right bent limb, a middle peak corresponds to the first center column and a leftmost peak corresponds to the left bent limb, the third plane is between the leftmost peak and the middle peak, and the first plane is between the middle peak and the rightmost peak;
• step 2), using the cogging mill to further cog down the mountain shaped middle billet obtained in step 1), and the mountain shaped middle billet is rolled by 1 to 4 second cogging holes, the second cogging holes comprising a seventh inclined plane, an eighth inclined plane, a ninth inclined plane, a tenth inclined plane, an eleventh inclined plane and a twelfth inclined plane, as well as a fifth plane, a sixth plane and a seventh plane, wherein the seventh inclined plane and the eighth inclined plane cooperate with the sixth plane to gradually flatten and thin the right bent limb of the mountain shaped middle billet to form a right flat limb, the ninth inclined plane, the fifth plane, and the tenth inclined plane cooperate with an arc segment to gradually thin and grow the first center column to form a second center column, and to extrude the fourth plane out into the arc segment, the eleventh inclined plane and the twelfth inclined plane cooperate with the seventh plane to gradually flatten and thin the left bent limb to form a left flat limb, a cross-section of the mountain shaped middle billet changes from the mountain shape to an inverted T-shape, thus obtaining an inverted T-shaped middle billet;
• step 3) roughly rolling the inverted T-shaped middle billet obtained by cogging down the first cogging hole and the second cogging hole to reduce the thickness and increase the width of the billet;
• step 4) performing finish rolling on the rough rolled billet in step 3, and accurately shape each part of the billet corresponding to a main plate, a side wing, and a tooth plate of the single-tooth track plate to obtain the single-tooth track plate, wherein the right flat limb is rolled into the main plate of the single-tooth track plate, the second center column is rolled into the side wing of the single-tooth track plate, and the left flat limb is rolled into the tooth plate of the single-tooth track plate,
• wherein the single-tooth track plate cogging-down pass comprises the first cogging hole and the second cogging hole, wherein the first cogging hole is formed by a first upper roller and a first lower roller of the cogging mill, and the second cogging hole is formed by a second upper roller and a second lower roller of the cogging mill,
• wherein the first cogging hole is a front hole, and the first cogging hole is used to extrude the rectangular continuous casting billet into the mountain shaped middle billet including the right bent limb, the first center column, and the left bent limb,
• wherein the second cogging hole is a rear hole, the second cogging hole is used to extrude the mountain shaped middle billet into the inverted T-shaped middle billet including the right flat limb, the second center column, and the left flat limb,
• wherein a lower surface of the first upper roller includes the first inclined plane, the first plane, the second inclined plane, the second plane, the third inclined plane, the third plane, and the fourth inclined plane,
• the first inclined plane, the first plane, the second inclined plane, the second plane, the third inclined plane, the third plane, and the fourth inclined plane are sequentially connected,
• the first plane and the third plane are located on a same horizontal plane, the first inclined plane, the second inclined plane, the third inclined plane, and the fourth inclined plane are all located above the first plane,
• the second plane is parallel to the first plane, the second inclined plane, the second plane, and the third inclined plane form a trapezoidal groove on the lower surface of the first upper roller.
• wherein an angle α between the first inclined plane and the first plane is 30°-70°,
• an angle β between the second inclined plane and the first plane is 65°-88°,
• an angle γ between the third inclined plane and the third plane is 65°-88°,
• an angle δ between the fourth inclined plane and the third plane is 30°-70°,
• specifically, a smooth transition is achieved between the second inclined plane and the second plane, between the second plane and the third inclined plane through an arc with a radius of 10 mm to 30 mm,
• a smooth transition is achieved between the first inclined plane and the first plane, between the first plane and the second inclined plane, between the third inclined plane and the third plane, and between the third plane and the fourth inclined plane through an arc with a radius of 25 mm to 60 mm,
• specifically, a length of the first inclined plane is B1, and a vertical distance between the second plane and the first plane is H1, and B1:H1=0.7˜2:1,
• a length of the fourth inclined plane is B2, and B2:H1=0.5˜1.2:1.