Titanium plate rolling method

Abstract

The invention provides a titanium plate rolling method. The titanium plate rolling method comprises the following steps that (1) a plate blank of a pulse type heating furnace is adopted for heating; and (2) controlled rolling is conducted on the heated plate blank at the high-temperature section through a constant rolling reduction method, and controlled rolling is conducted on the plate blank at the low-temperature section through a rolling reduction decreasing method. According to the method, a process strategy of high-temperature fast rolling is used, after being heated, a plate blank is conveyed to a rolling mill at the fastest roller way speed to be rolled, in the whole process, the temperature is controlled in an alpha single-phase region to control rolling, a constant rolling reduction method is adopted to control rolling at a high-temperature section, the rolling force fluctuation at the stage is small, and the plate shape control is good; rolling is controlled in a low-temperature section by adopting a rolling reduction decreasing method, and the rolling temperature is controlled within a process requirement range, so that the shape of the titanium plate is ensured, and surface cracks of the plate are greatly reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of titanium plates and relates to a titanium plate rolling method. Background Art

[0002] Titanium and titanium alloy plates have been widely used in aerospace, machinery manufacturing, weapons production, chemical and medical fields due to their low density, high specific strength, good toughness, strong corrosion resistance, and high temperature resistance. With the rapid development of modern science and technology, the development of the titanium industry has entered a new normal, and national defense and scientific and technological development require a large number of titanium plates to meet the demand.

[0003] However, the domestic titanium plate production started late, the production technology is not fully mastered, the rolling equipment is backward, the process automation is low, the production capacity and output are low, especially there are many technical difficulties in the titanium plate rolling process. Unlike the rolling of ordinary metal plates, the titanium plate material has poor thermal conductivity and a narrow rolling temperature window. If the rolling temperature is too high or the rolling deformation is too large, the temperature in the center of the rolled piece will rise sharply, and even enter β phase region, which can easily lead to the rapid growth of the already broken grains, causing organizational defects and further affecting the mechanical properties of the material; if the rolling temperature is low, the rolling mill load is large, and the plate has more edge cracks and surface cracks. On the other hand, during the rolling process of titanium plates, due to the large temperature difference between the upper and lower surfaces, the elongation of the upper surface is generally greater than that of the lower surface, and the plate is prone to buckling. It is easy to hit the working roll guard plate during the bite stage, causing scratches on the lower surface and even wrapping around the roll; when the surface temperature drops beyond the process window, cracks are easily generated on the upper and lower surfaces, and the customer's grinding volume is large, the yield rate of titanium plates is reduced, and the production cost is increased. These have increased the difficulty and production cost of titanium plate rolling, and also put forward higher requirements for titanium plate rolling. Summary of the invention

[0004] The purpose of the present invention is to provide a titanium plate rolling method in view of the problems existing in the prior art.

[0005] To this end, the present invention adopts the following technical solutions: A titanium plate rolling method comprises the following steps: (1) The slab is heated to 820-840°C using a pulse heating furnace for 270-290 minutes; (2) The heated slab is rolled using a constant reduction method in the high temperature section, and the slab is rolled using a decreasing reduction method in the low temperature section; Furthermore, the temperature of the high temperature section in step (1) is 720-840°C.

[0006] Furthermore, in the step (1), the constant reduction rolling method is performed by 6 passes, the starting rolling temperature is 770-790° C., and the reduction rate of each pass is 9-11%.

[0007] Furthermore, the low temperature section in step (2) is below 700°C.

[0008] Furthermore, in the step (2), the rolling is performed in 8 passes with a reduction reduction method, the final rolling temperature is 670-690°C, the reduction rate of the first pass is 9-11%, and the reduction rate of each of the remaining passes is reduced by 1%.

[0009] Furthermore, in the step (2), the rolling mill guard plate is chamfered before rolling.

[0010] The beneficial effects of the present invention are as follows: a process strategy of rapid temperature rolling is adopted, and after the slab is heated, it is transported to the rolling mill at the fastest roller speed for rolling. During the whole process, the temperature is controlled in the α single-phase region to control the rolling, and a constant pressure reduction method is adopted to control the rolling in the high temperature section. The rolling force fluctuation in this stage is small, and the plate shape is well controlled; in the low temperature section, a reduction reduction method is adopted to control the rolling, and the rolling temperature is controlled within the range of process requirements, which not only ensures the shape of the titanium plate, but also greatly reduces the surface cracks of the plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the structure of the guard plate after the edge is chamfered in the present invention; In the figure, 1-lower working roll guard plate, 2-edge. DETAILED DESCRIPTION

[0012] The present invention is described in detail below in conjunction with embodiments: A titanium plate rolling method comprises the following steps: (1) The slab is heated in a pulse heating furnace at 820-840°C for 270-290 minutes. In this embodiment, the slab is heated to 820°C for 270 minutes. The composition and percentage of the substances contained in the slab are consistent with those of the existing conventional titanium plate. Compared with continuous combustion, the pulse combustion control technology heating furnace has the advantages of precise temperature control and less oxidation and burning. At the same time, it reduces the heating temperature at each stage and reduces the time in the furnace to reduce the generation of oxidation and burning.

[0013] (2) The heated slab is quickly transported to the rolling mill for rolling. The temperature is controlled at αSingle-phase zone controlled rolling, the slab is rolled by constant reduction method in the high temperature section, the temperature of the high temperature section is 720-840°C, specifically, 6 passes are used for rolling during constant reduction method rolling, the start rolling temperature is 770-790°C, the start rolling temperature in this embodiment is 780°C, the reduction rate of each pass is 9-11%, the reduction rate of each pass in this embodiment is 10%, the rolling force fluctuation is small at this stage, and the plate shape is well controlled, the slab is controlled by reduction reduction method in the low temperature section, the temperature of the low temperature section is below 700°C, specifically, 8 passes are used for rolling by reduction reduction method, the final rolling temperature is 670-690°C, 680°C in this embodiment, the reduction rate of the first pass is 9-11%, 10% in this embodiment, and the reduction rate of each pass is reduced by 1%, that is, the reduction rate of the last pass is 3%, and the rolling temperature is controlled within the process requirements, which not only ensures the shape of the titanium plate, but also greatly reduces the surface cracks of the plate.

[0014] In addition, the titanium plate will buckle during the rolling process, and will hit and rub the edge 2 of the lower working roll guard 1 of the rolling mill during the biting stage. Since the edge 2 of the lower working roll guard 1 is angular and the titanium plate has deep scratches, the lower surface of the finished product will be severely cracked and waxed. The edge 2 is chamfered and rounded (such as Figure 1 As shown in the figure, the rigid impact between the rolled piece and the guard plate is effectively avoided, and the surface quality of the titanium plate is improved.

Claims

1. A titanium plate rolling method, characterized in that: The following steps are involved: (1) The slab is heated to 820-840°C using a pulse heating furnace for 270-290 minutes; (2) The heated slab is rolled using a constant reduction method in the high temperature section, and the slab is rolled using a decreasing reduction method in the low temperature section; The titanium plate rolling method according to claim 1 is characterized in that the temperature of the high temperature section in step (1) is 720-840°C.

2. A titanium plate rolling method according to claim 1, characterized in that: In the step (1), the constant reduction rolling method is performed in 6 passes, the starting rolling temperature is 770-790° C., and the reduction rate of each pass is 9-11%.

3. A titanium plate rolling method according to claim 1, characterized in that: The temperature of the low temperature section in step (2) is below 700°C.

4. A titanium plate rolling method according to claim 1, characterized in that: In the step (2), the rolling is performed by the reduction reduction method in 8 passes, the final rolling temperature is 670-690° C., the reduction rate of the first pass is 9-11%, and the reduction rate of each of the remaining passes is reduced by 1%.

5. A titanium plate rolling method according to claim 1, characterized in that: In the step (2), the rolling mill guard plate is chamfered before rolling.

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