CN118756080A - Titanium alloy cold-rolled coil and preparation method thereof - Google Patents

Abstract

The invention relates to the technical field of titanium alloy cold-rolled coil processing, in particular to a titanium alloy cold-rolled coil and a preparation method thereof. The preparation method comprises the steps of performing first heating treatment on the thick titanium alloy strip coil; cooling treatment; performing secondary heating treatment; carrying out hot rolling treatment; heating for the third time; surface treatment; cold rolling treatment; and (3) post-treating to obtain the titanium alloy cold-rolled coil with the thickness h ₃ of 0.50-2.00 mm. The titanium alloy cold-rolled coil is prepared by the preparation method. The invention solves the problems of low yield, long production period, poor batch stability, large anisotropy and obvious surface stripes existing in the prior art.

Description

Titanium alloy cold-rolled coil and preparation method thereof

Technical Field

The invention relates to the technical field of titanium alloy cold-rolled coil processing, and in particular to a titanium alloy cold-rolled coil and a preparation method thereof.

Background Art

At present, the industry mainly uses traditional sheet production technology to produce titanium alloy thin plates, among which the thickness of titanium alloy thin plates is generally 0.50-4.75mm. Specifically, the traditional sheet production process improves the uniformity of material structure and performance by cutting width reversal during the rolling process of titanium alloy thin plates. However, the traditional sheet production process generally has problems such as small single batch production volume, multiple processes, low yield rate, long production cycle and poor batch stability.

In addition, the industry also uses traditional coil production technology to produce titanium alloy sheets. Due to its inherent processing method, the traditional coil production process can only be continuously processed and deformed along a single rolling direction, and there are problems such as large anisotropy (such as causing the transverse and longitudinal yield strength R _p0.2 deviation to reach 150MPa) and obvious surface stripes (such as the appearance of chaotic and uneven striped structures), which cannot meet the use requirements and urgent needs of the high-end market and customers.

In summary, it is necessary to provide a titanium alloy cold-rolled coil and a preparation method thereof to solve the problems existing in the prior art such as low yield, long production cycle, poor batch stability, large anisotropy and obvious surface stripes.

Summary of the invention

The object of the present invention is to provide a titanium alloy cold-rolled coil and a preparation method thereof. The specific technical scheme is as follows:

In a first aspect, the present invention provides a method for preparing a titanium alloy cold-rolled coil, comprising:

Step S1, subjecting a titanium alloy coil having a thickness _h1 of 4.00-10.00 mm to a first heating treatment;

Step S2, cooling the titanium alloy coil after the first heating;

Step S3, subjecting the titanium alloy coil after cooling to a second heating treatment;

Step S4, hot rolling the titanium alloy strip coil after the second heating treatment; wherein the rolling deformation of the hot rolling treatment is controlled at 30% to 50%, and a titanium alloy hot rolled coil with a thickness _h2 of 2.00-6.00 mm is obtained;

Step S5, subjecting the titanium alloy hot-rolled coil having a thickness _h2 of 2.00-6.00 mm to a third heating treatment;

Step S6, performing surface treatment on the titanium alloy hot-rolled coil after the third heating treatment;

Step S7, subjecting the titanium alloy hot-rolled coil after the surface treatment to a multi-pass cold rolling treatment to obtain a titanium alloy cold-rolled coil with a thickness _h3 of 0.50-2.00 mm; wherein the rolling deformation amount of each rolling pass is controlled at 20% to 30%, and the cumulative deformation amount of the cold rolling treatment is not less than 50%;

Step S8, post-processing the titanium alloy cold-rolled coil to obtain a titanium alloy cold-rolled coil with a thickness _h3 of 0.50-2.00 mm; the post-processing includes performing a finished product annealing treatment on the titanium alloy cold-rolled coil.

Optionally, the heating temperature of the first heating treatment is T _β -30°C to T _β +50°C, and the heat preservation time is h ₁ ×1.0 min/mm to h ₁ ×1.5h ₁ min/mm.

Optionally, the cooling treatment includes water cooling or air cooling; the cooling rate is ≥10°C/s, and the coiling temperature is ≤80°C.

Optionally, the heating temperature of the second heating treatment is T _β -100° C. to T _β -30° C., and the heat preservation time is h ₁ ×1.0 min/mm to h ₁ ×1.5h ₁ min/mm.

Optionally, the heating temperature of the third heating treatment is T _β -150° C. to T _β -100° C., and the heat preservation time is h ₂ ×1.0 min/mm to h ₂ ×1.5 min/mm.

Optionally, the method for preparing the titanium alloy cold-rolled coil further includes a degreasing treatment, and the degreasing treatment is arranged between step S7 and step S8.

Optionally, the heating temperature of the finished product annealing treatment is T _β -150° C. to T _β -100° C., and the holding time is h ₃ ×1.0 min/mm to h ₃ ×1.5 min/mm.

Optionally, the post-processing further includes straightening the titanium alloy cold-rolled coil after the finished annealing treatment.

In a second aspect, the present invention provides a titanium alloy cold-rolled coil, which is prepared by the method for preparing the titanium alloy cold-rolled coil.

Optionally, the titanium alloy cold-rolled coil includes TC4 titanium alloy cold-rolled coil.

The application of the technical solution of the present invention has at least the following beneficial effects:

(1) The preparation method of titanium alloy cold-rolled coil provided by the present invention is designed for titanium alloy strip coils with a thickness _h1 of 4.00-10.00 mm after pre-hot rolling. Specifically, the present invention combines the first heating treatment of step S1 with the cooling treatment of step S2 to improve the strip-like structure caused by continuous rolling of the pre-hot-rolled titanium alloy strip coil during the hot rolling process, so that the strip-like structure is homogenized and the surface condition is improved; considering that the titanium alloy strip coil after homogenization has high strength and poor plasticity, the present invention combines the second heating treatment of step S3 with the hot rolling treatment of step S4, and through the hot rolling treatment of the titanium alloy strip coil, it is convenient to carry out large deformation rolling and quickly crush the grain structure, which provides a good performance for the subsequent cold rolling treatment of step S7. The invention can produce titanium alloy hot-rolled coils of excellent quality; considering the hardening in the hot rolling treatment in step S4, the third heating treatment in step S5 and the cold rolling treatment in step S7 are combined to further reduce the thickness of the grain structure after recrystallization annealing to ensure the thickness accuracy and plate quality of the finished product; the surface treatment between step S5 and step S7 is to remove the oxide layer and the air absorption layer on the surface of the titanium alloy hot-rolled coil, including surface inclusions and pits and other defects, to ensure that the surface quality requirements of the finished product are met; in step S8, the finished product annealing treatment is also included to remove the hardening in the cold rolling process, so that the grain structure meets the organizational performance requirements of the finished product after recrystallization. Therefore, the invention can prepare a 0.5-2.0mm titanium alloy cold-rolled coil with a fine and uniform equiaxed spheroidized structure, the α phase grain size is ≤15μm, the anisotropy (the deviation of the transverse and longitudinal yield strength R _p0.2 is controlled within 50MPa) is small, and there are no obvious stripes on the surface.

(2) In terms of economic benefits, compared with the traditional sheet production process, the preparation method of titanium alloy cold-rolled coil provided by the present invention can shorten the process flow and cycle by 10 to 20 days, improve the yield rate (5 to 10%), greatly improve the production efficiency and technical and economic indicators, reduce costs while improving quality, and realize the efficient, batch and stable production of TC4 thin-gauge plates and strips.

In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

FIG1 is a metallographic structure diagram of a titanium alloy cold-rolled coil prepared in Example 1 of the present invention;

FIG2 is a metallographic structure diagram of a titanium alloy cold-rolled coil prepared in Example 2 of the present invention;

FIG3 is a metallographic structure diagram of a titanium alloy cold-rolled coil prepared in Example 3 of the present invention;

FIG4 is a metallographic structure diagram of the titanium alloy cold-rolled coil prepared in Comparative Example 1 of the present invention;

FIG5 is a metallographic structure diagram of the titanium alloy cold-rolled coil prepared in Comparative Example 2 of the present invention;

FIG6 is a metallographic structure diagram of the titanium alloy cold-rolled coil prepared in Comparative Example 3 of the present invention;

FIG7 is a metallographic structure diagram of the titanium alloy cold-rolled coil prepared in Comparative Example 4 of the present invention;

FIG8 is a metallographic structure diagram of the titanium alloy cold-rolled coil prepared in Comparative Example 5 of the present invention;

FIG9 is a metallographic structure diagram of the titanium alloy cold-rolled coil prepared in Comparative Example 6 of the present invention;

FIG. 10 is a metallographic structure diagram of the titanium alloy cold-rolled coil prepared in Comparative Example 7 of the present invention.

DETAILED DESCRIPTION

The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

Embodiment 1:

A method for preparing a titanium alloy cold-rolled coil, comprising:

Step S1, using a continuous annealing furnace to perform a first heating treatment on a titanium alloy coil with a thickness _h1 of 8.00 mm (specifically, a TC4 titanium alloy coil with a T _β of 985° C.); the heating temperature of the first heating treatment is 980° C., and the holding time is 10 min;

Step S2, cooling the titanium alloy coil after the first heating; the cooling treatment is air cooling; the cooling rate is 10°C/s, and the coiling temperature is 80°C;

Step S3, subjecting the titanium alloy coil after cooling to a second heating treatment in a continuous annealing furnace; the heating temperature of the second heating treatment is 920° C., and the holding time is 12 minutes;

Step S4, subjecting the titanium alloy strip coil after the second heating treatment to a hot rolling process; wherein the rolling deformation amount of the hot rolling process is controlled at 50%, and a titanium alloy hot rolled coil with a thickness _h2 of 4.00 mm is obtained;

Step S5, subjecting the titanium alloy hot-rolled coil having a thickness _h2 of 4.00 mm to a third heating treatment using a continuous annealing furnace; the heating temperature of the third heating treatment is 850° C., and the holding time is 5 min;

Step S6, performing surface treatment on the titanium alloy hot-rolled coil after the third heating treatment to remove the oxide layer and the air absorption layer on the surface of the titanium alloy hot-rolled coil, and then trimming;

Step S7, subjecting the titanium alloy hot-rolled coil after the surface treatment to three cold rolling processes to obtain a titanium alloy cold-rolled coil with a thickness _h3 of 1.50 mm; wherein the rolling deformation amounts of the three rolling processes are controlled at 28%, 28% and 26% respectively, and the cumulative deformation amount of the cold rolling process is 62.5%;

Step S8: subjecting the titanium alloy cold-rolled coil to degreasing treatment and post-treatment in sequence to obtain a titanium alloy cold-rolled coil with a thickness _h3 of 1.50 mm.

The degreasing treatment is a conventional degreasing and cleaning process, which is used to achieve degreasing and cleaning of titanium alloy cold-rolled coils.

The post-treatment includes using a continuous annealing furnace to perform a finished product annealing treatment on the titanium alloy cold-rolled coil. The heating temperature of the finished product annealing treatment is 880° C. and the holding time is 2 minutes.

The post-processing also includes performing conventional straightening treatment on the titanium alloy cold-rolled coil after the finished annealing treatment, so as to straighten the titanium alloy cold-rolled coil.

The present invention further provides Embodiment 2 and Embodiment 3 based on Embodiment 1. For specific parameter changes, see Table 1.

Table 1 Specific parameter changes of Examples 1-3

Comparative Example 1:

Different from the first embodiment, step S2 and step S3 are not adopted.

Comparative Example 2:

Different from the first embodiment, step S4 and step S5 are not adopted.

Comparative Example 3:

Different from the first embodiment, step S7 is not adopted.

Comparative Example 4:

Different from Example 1, the rolling deformation amount of the hot rolling treatment in step S4 is 25%.

Comparative Example 5:

Different from Example 1, the rolling deformation amount of the hot rolling treatment in step S4 is 55%.

Comparative Example 6:

Different from Example 1, the rolling deformation amounts of the three rolling passes of the cold rolling treatment in step S7 are controlled at 20%, 18% and 15% respectively, and the cumulative deformation amount of the cold rolling treatment is 45%.

Comparative Example 7:

Different from Example 1, the rolling deformation amounts of the three rolling processes of the cold rolling treatment in step S7 are controlled at 35%, 32% and 28% respectively, and the cumulative deformation amount of the cold rolling treatment is 68%.

The titanium alloy cold-rolled coils prepared in Examples 1-3 and Comparative Examples 1-7 were respectively subjected to performance tests as shown in Table 2. In Table 2, R _m represents tensile strength; R _p0.2 represents yield strength; A represents elongation, specifically, in the transverse direction, it represents transverse elongation, and in the longitudinal direction, it represents longitudinal elongation.

Table 2 Performance test results

As shown in Table 2, compared with Comparative Examples 1-7, the present invention can prepare titanium alloy cold-rolled coils whose tensile strength R _m , yield strength R _p0.2 and elongation A meet the technical standards by using Examples 1-3, and the anisotropy (the deviation of the transverse and longitudinal yield strength R _p0.2 is controlled within 50 MPa) is small.

The titanium alloy cold-rolled coil prepared in Comparative Example 1 has an R _p0.2 deviation greater than 50 MPa, showing poor anisotropy; this is because Comparative Example 1 does not adopt the cooling treatment in step S2 and the second heating treatment in step S3, so that the grain structure of the titanium alloy cold-rolled coil is not homogenized.

The titanium alloy cold-rolled coil prepared in Comparative Example 2 has an R _p0.2 deviation greater than 50 MPa, showing poor anisotropy; this is because Comparative Example 2 does not adopt the hot rolling treatment in step S4 and the third heating treatment in step S5, so that the grain structure of the titanium alloy cold-rolled coil is not broken and homogenized.

The titanium alloy cold-rolled coil prepared in Comparative Example 3 has an R _p0.2 deviation greater than 50 MPa, showing poor anisotropy; its longitudinal elongation is lower than the technical standard; this is because Comparative Example 3 does not adopt step S7 cold rolling treatment, resulting in incomplete crushing of the grain structure of the titanium alloy cold-rolled coil.

The elongation A of the titanium alloy cold-rolled coil prepared in Comparative Example 4 is lower than the technical standard in both the longitudinal and transverse directions; this is because the rolling deformation amount of Comparative Example 4 during the hot rolling treatment in step S4 is too small, resulting in incomplete and uneven grain structure crushing of the titanium alloy cold-rolled coil.

The titanium alloy cold-rolled coil prepared in Comparative Example 5 has an elongation A that meets the technical standards in the longitudinal and transverse directions, but exhibits poor elongation; this is because the rolling deformation amount of Comparative Example 5 during the hot rolling treatment in step S4 is too large, resulting in uneven grain structure breakage of the titanium alloy cold-rolled coil.

The elongation A of the titanium alloy cold-rolled coil prepared in Comparative Example 6 is lower than the technical standard in both the longitudinal and transverse directions; this is because the rolling deformation amount of Comparative Example 6 during the cold rolling treatment in step S7 is too small, resulting in incomplete and uneven grain structure crushing of the titanium alloy cold-rolled coil.

The titanium alloy cold-rolled coil prepared in Comparative Example 7 has an R _p0.2 deviation greater than 50 MPa, showing poor anisotropy; although its elongation A meets the technical standards in the longitudinal and transverse directions, it shows poor elongation; this is because the rolling deformation amount of Comparative Example 7 during the cold rolling treatment in step S7 is too large, resulting in uneven grain structure breakage of the titanium alloy cold-rolled coil.

The titanium alloy cold-rolled coils prepared in Examples 1-3 and Comparative Examples 1-8 were sampled for metallographic structure testing. The testing method is as follows: the metallographic structure testing is performed according to the high and low magnification structure testing method of two-phase titanium alloy in GB/T 5168. The test results are shown in Figures 1 to 10.

As shown in Figures 1 to 10, through the titanium alloy cold-rolled coil and the preparation method thereof of the present invention, through the effective coupling of multi-step heat treatment and rolling deformation, the prepared titanium alloy cold-rolled coil can have a fine and uniform equiaxed spheroidized structure, and the α phase grain size is controlled to be ≤15μm, wherein the α phase grain size is measured by the GB/T 6394 metal average grain size determination method.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims (10)

1. A method for preparing a titanium alloy cold rolled coil, comprising the steps of:

S1, performing primary heating treatment on a titanium alloy strip coil with the thickness h ₁ of 4.00-10.00 mm;

s2, cooling the titanium alloy strip coil after the first heating;

s3, performing secondary heating treatment on the cooled titanium alloy strip coil;

S4, carrying out hot rolling treatment on the titanium alloy strip coil subjected to the second heating treatment; wherein, the rolling deformation of the hot rolling treatment is controlled to be 30-50 percent, and the titanium alloy hot rolled coil with the thickness h ₂ of 2.00-6.00mm is obtained;

s5, performing third heating treatment on the titanium alloy hot rolled coil with the thickness h ₂ of 2.00-6.00 mm;

S6, carrying out surface treatment on the titanium alloy hot rolled coil subjected to the third heating treatment;

S7, performing multi-pass cold rolling treatment on the titanium alloy hot rolled coil subjected to the surface treatment to obtain a titanium alloy cold rolled coil with the thickness h ₃ of 0.50-2.00 mm; wherein the rolling deformation of each rolling process is controlled to be 20% -30%, and the accumulated deformation of the cold rolling treatment is not less than 50%;

S8, performing post-treatment on the titanium alloy cold-rolled coil to obtain a titanium alloy cold-rolled coil with the thickness h ₃ of 0.50-2.00 mm; the post-treatment comprises the step of carrying out finished product annealing treatment on the titanium alloy cold-rolled coil.

2. The method for preparing a cold rolled titanium alloy coil according to claim 1, wherein the heating temperature of the first heating treatment is T _β-30℃～T_β +50 ℃, and the heat preservation time is h ₁×1.0min/mm～h₁×1.5h₁ min/mm.

3. The method of producing a cold rolled titanium alloy coil according to claim 1, wherein the cooling treatment includes water cooling or air cooling; the cooling speed is more than or equal to 10 ℃/s, and the coiling temperature is less than or equal to 80 ℃.

4. The method for producing a cold rolled titanium alloy coil according to claim 1, wherein the heating temperature of the second heating treatment is T _β-100℃～T_β -30 ℃ and the holding time is h ₁×1.0min/mm～h₁×1.5h₁ min/mm.

5. The method for producing a cold rolled titanium alloy coil according to claim 1, wherein the third heating treatment is performed at a heating temperature of T _β-150℃～T_β -100 ℃ for a holding time of h ₂×1.0min/mm～h₂ x 1.5min/mm.

6. The method of producing a cold rolled titanium alloy coil according to claim 1, further comprising a degreasing treatment, the degreasing treatment being provided between step S7 and step S8.

7. The method for producing a cold rolled titanium alloy coil according to claim 1, wherein the heating temperature of the final annealing treatment is T _β-150℃～T_β -100 ℃ and the holding time is h ₃×1.0min/mm～h₃ x 1.5min/mm.

8. The method of producing a cold rolled titanium alloy coil according to claim 1, wherein the post-treatment further comprises straightening the finished annealed cold rolled titanium alloy coil.

9. A titanium alloy cold rolled coil prepared by the method of any one of claims 1 to 8.

10. The titanium alloy cold rolled coil of claim 9, wherein the titanium alloy cold rolled coil comprises a TC4 titanium alloy cold rolled coil.