CN105678466A - Method for judging section quality of cold-rolled base material - Google Patents

Abstract

The invention relates to a method for judging the section quality of a cold-rolled base material. The cold-rolled base material of the method is a main product of hot rolled strip steel, the section quality mainly includes degree of convexity, wedge shape and local high points, after measured data are obtained from a section detection instrument, and the multi-interval hit rate and variance of the section quality of the cold rolled base material are calculated and are compared with a set hit rate threshold value and variance threshold value in sequence and are synthesized, thereby obtaining a conclusion of a first-class product, a second-class product or an unqualified product. The method for judging the section quality of the cold rolled base material proposed by the invention fully considers real demands of downstream users for the cold rolled base material, has essential difference compared with the traditional single hit rate, and provides an effective method for evaluation of the section quality of the cold rolled base material.

Description

A kind of cross section quality decision method of cold rolling base

Technical field

The present invention relates to machinery and automation on metallurgy, rolling technique, refer specifically to the cross section quality decision method of a kind of cold rolling base.

Technical background

Cold rolling base is the major product of hot-strip, provides raw material for cold rolling process. Cold rolling base section configuration is had strict requirement by cold rolling process, if section configuration is not good, it is easy to cause that muscle has occurred in cold rolling process, the problem such as the little broken sea of edge and rolling stability. The section configuration quality of cold rolling base mainly includes convexity, wedge shape and local high spot, its camber refers to the difference of strip steel central point thickness and the strip steel two a range of thickness average value of lateral extent edge, C can be obtained again according to two lateral extent sizes (such as 25mm, 40mm, 75mm etc.)₂₅, C₄₀, C₇₅, usual more employing C₄₀As convexity index; Wedge shape refers to the difference of the strip steel two a range of thickness of lateral extent edge, can obtain again W according to two lateral extent sizes (such as 25mm, 40mm, 75mm etc.)₂₅, W₄₀, W₇₅, usual more employing W₄₀As wedge shape index; Local high spot H_sRefer to the difference of section abnormity point maximum and matched curve correspondence position. For 40mm position, being illustrated in figure 1 the schematic diagram of cold rolling base section, method for expressing and the computational methods of its camber and wedge shape are as follows:

C₄₀=H_c–(H_d40+H_o40)/2

W₄₀=H_d40-H_o40

Wherein: H_cFor the middle dot thickness of cold rolling base section, H_d40And H_o40The respectively belt steel thickness of transmission side and fore side distance edge 40mm. C₄₀、W₄₀、H_sCan directly obtain by being arranged on the bottom profiler at scene, the time of general about 1 second can measure one group of data of cross section taken in correspondence, return to process control computer for analyzing and achieving, assume that certain strip steel total length is 1000m, mill speed is 10m/s, the rolling time of this strip steel is 100s, altogether can obtain 100 groups of C₄₀、W₄₀、H_sMeasured data.

Generally, the cross section quality decision method of cold rolling base mainly adopts single hit rate statistical, namely convexity hit rate or wedge shape hit rate is adopted to represent, first convexity desired value and positive and negative deviation and wedge shape desired value and positive and negative deviation are set, calculate convexity respectively and wedge shape measured value falls the quantity that the corresponding deviation of target is interval, obtain convexity and wedge shape hit rate, judge to control quality control precision by the size of hit rate.This method is also widely used in the various quality judgings of industrial system, but, for cold rolling base, this method also exists following deficiency:

1) cold rolling base can tolerate that convexity is bigger than normal, but it is less than normal to can't stand convexity, for this, the positive negative direction of convexity tolerance also exists asymmetric situation in actual use, and same hit rate has different downstream user and experiences (such as super equally lower limit and super lower proportion ratio);

2) if the big ups and downs in the margin of tolerance of the convexity of cold rolling base and wedge shape, even if there being higher hit rate, the result of use of downstream user is also undesirable;

3) cold rolling base is strict to the demand of cross section quality, and existing convexity and wedge shape calculate independent hit rate respectively, a not comprehensive section evaluation criterion.

At present the cross section quality of cold rolling base is judged that research is considerably less, such as document " hot rolling quality judging thought and realization " (metallurgical automation, supplementary issue in 2006, S2, introducing the determination processing of coils of hot-rolled steel overall dimensions in 72-715), the method for Main Basis is that the control rate that plate profile instrument table detected value and L3 are assigned simply contrasts, and draws result of determination, this is the hit rate statistical that above-mentioned described employing is single, and its shortcoming is also in above-mentioned middle statement. The shape wave of strip steel is mainly carried out quality judging by patent " a kind of online decision method of the strip shape quality suitable in hot rolled thin specification strip steel " (grant number: 201210135076.6), and cross section quality mentioned in this article judges judging there is essential distinction in content. Patent " a kind of cold rolling flatness quality judging method based on fuzzy algorithmic approach " (application number: 201510048339.3) refer to the quality judging method of a kind of cold rolling flatness, and the cross section quality that text is mentioned judges judging to have equally in content essential difference.

For this, for solving problem above, the present invention proposes the cross section quality decision method of a kind of cold rolling base, after obtaining measured data from section instrumentation, by calculating how interval hit rate and the variance of cold rolling base cross section quality, and be sequentially carried out and compare with the hit rate threshold value set, variance threshold values and comprehensively, obtain Grade A, goods of inferior quality or defective work conclusion. The cold rolling base cross section quality decision method that the present invention proposes has taken into full account the downstream user real demand to cold rolling base, judges to compare the difference with essence with traditional single hit rate, and the cross section quality evaluation for cold rolling base provides effective ways.

Summary of the invention

Based on above analysis, the cross section quality decision method of cold rolling base needs to consider the cold-rolled process actual demand to incoming hot rolled slab so that result of determination more can press close to service condition, and for this, cross section quality proposed by the invention judges to need to consider following aspect:

1) decision process needs to consider the impact of convexity, wedge shape and local high spot;

2) from subitem result of determination, synthetic determination result should be able to be obtained by certain rule;

3) during subitem judges, it is contemplated that lower procedure is to the degrees of tolerance difference of lower deviation in convexity.

A kind of cold rolling base cross section quality decision method that the present invention is previously mentioned, it is characterised in that described method comprises the steps of:

Step 1: obtain cold rolling base total length cross section quality data from section instrumentation, including distance edge 40mm place convexity C₄₀, distance edge 40mm place wedge shape W₄₀, local high spot H_s;

Step 2: set convexity desired value C_A, convexity tolerance interval C, C=15 μm-20 μm;Carry out following convexity according to measured data and local high spot judge:

2.1 calculate convexity C₄₀Drop on [C_A-C,C_A+ C] interval hit rate P_c1, set hit rate threshold

Value σ c1, σ_c1=95.4%;

2.2 calculate convexity C₄₀Drop on [C_A-C,C_A+ 2C] hit rate P_c2, set hit rate threshold

Value σ_c2, σ_c2=95.4%;

2.3 calculate convexity C₄₀Variance P_c3, convexity variance threshold values scope σ_c3=8-10 μm;

2.4 obtain local high spot meansigma methods H_{s_avg}, local high spot threshold range σ_c4=15-20 μm;

2.5 convexitys and local high spot grade decision rule:

Grade A standard: P_c1>σ_c1And P_c3<σ_c3,H_{s_avg}<σ_c4;

Goods of inferior quality standard: be unsatisfactory for Grade A standard, but P_c2>σ_c2And H_{s_avg}<σ_c4;

Defective standard: be unsatisfactory for Grade A or goods of inferior quality standard;

Step 3: set wedge shape desired value W_A, W, W=15 μm-20 μm of wedge tolerance interval, carry out following wedge shape judgement according to measured data:

3.1 wedge shape W₄₀Drop on [W_A-W,W_A+ W] hit rate P_w1, set hit rate threshold value

σ_w1, σ_w1=95.4%;

3.2 wedge shape W₄₀Drop on [W_A-1.5W,W_A+ 1.5W] hit rate P_w2, set hit rate

Threshold value σ_w2, σ_w2=95.4%;

3.3 wedge shape W₄₀Variance P_w3, wedge shape variance threshold values σ_w3=8-10 μm;

3.4 wedge shape grade decision rules:

Grade A standard: P_w1>σ_w1And P_w3<σ_w3;

Goods of inferior quality standard: be unsatisfactory for Grade A standard, P_w2>σ_w2;

Defective standard: be unsatisfactory for Grade A or goods of inferior quality standard;

Step 4: judging to judge with wedge shape grade in conjunction with convexity and local high spot grade, taking both the lowest class is principle, obtains cold rolling base cross section quality synthetic determination result as follows:

1) if convexity and local high spot judge grade: Grade A, wedge shape judges grade: Grade A, then synthetic determination grade: Grade A;

2) if convexity and local high spot judge grade: Grade A, wedge shape judges grade: goods of inferior quality, then synthetic determination grade: goods of inferior quality;

3) if convexity and local high spot judge grade: Grade A, wedge shape judges grade: defective, then synthetic determination grade: defective;

4) if convexity and local high spot judge grade: goods of inferior quality, wedge shape judges grade: Grade A, then synthetic determination grade: goods of inferior quality;

5) if convexity and local high spot judge grade: goods of inferior quality, wedge shape judges grade: goods of inferior quality, then synthetic determination grade: goods of inferior quality;

6) if convexity and local high spot judge grade: goods of inferior quality, wedge shape judges grade: defective, then synthetic determination grade: defective;

7) if convexity and local high spot judge grade: defective, wedge shape judges grade: Grade A, then synthetic determination grade: defective;

8) if convexity and local high spot judge grade: defective, wedge shape judges grade: goods of inferior quality, then synthetic determination grade: defective;

9) if convexity and local high spot judge grade: defective, wedge shape judges grade: defective, then synthetic determination grade: defective.

The flow chart of decision method is as shown in Figure 2. The present invention transforms without existing system is carried out hardware, significantly revise without to software system structure, have only in existing system, quality judging method and algorithm are again write and replaced and can realize the effective judgement to cold rolling base cross section quality, it is possible to increased quality and early warning for enterprise provide useful help.

Accompanying drawing explanation

The schematic diagram of Fig. 1 cold rolling base section.

The cross section quality decision method flow chart of Fig. 2 cold rolling base.

Detailed description of the invention

Producing the trade mark for DC03 with certain iron and steel enterprise 1450mm hot-rolling mill, thickness specification is 4.0mm, and the cold rolling base that width specifications is 1275mm is example, introduces specific implementation of the patent mode.

Step 1: obtain cold rolling base total length cross section quality data from section instrumentation, including convexity, wedge shape, local high spot. As shown in the table, wherein, No is counting of this cold rolling base of altogether getting of section instrument, and entire volume strip steel gets 65 cross sections altogether in process of production; Time is the concrete time obtaining each cross section; The strip length position that StripLen is corresponding when being get each cross section; StripWid is the actual measurement width that each cross section is corresponding; C₄₀Convex value for each cross-sectional distance edge 40mm place; W₄₀Shim values for each cross-sectional distance edge 40mm place; H_sLocal high spot value for each cross section.

Step 2: set convexity desired value C_A=40 μm, convexity tolerance interval C=18 μm.

1) can calculate from table and obtain, convexity C₄₀Drop on [22 μm, 58 μm] interval hit rate P_c1=100%, set hit rate threshold value σ_c1=95.4%;

2) can calculate from table and obtain, convexity C₄₀Drop on the hit rate P of [22 μm, 76 μm]_c2=100%, set hit rate threshold value σ_c2=95.4%;

3) can calculate from table and obtain, convexity C₄₀Variance P_c3=4.64 μm, set convexity variance threshold values σ_c3=8 μm;

4) can calculate from table and obtain, local high spot meansigma methods H_{s_avg}=7.69 μm, set local high spot threshold value σ_c4=15 μm;

Can obtaining according to convexity and local high spot grade decision rule, the result of calculation of measured data meets Grade A standard: P_c1>σ_c1And P_c3<σ_c3, H_{s_avg}<σ_c4, judge to obtain this cold rolling base as Grade A by convexity and local high spot grade for this.

Step 3: set wedge shape desired value W_A=0 μm, wedge tolerance value W=20 μm.

1) can calculate from table and obtain, wedge shape W₄₀Drop on the hit rate P of [-20 μm, 20 μm]_w1=76.9%, set hit rate threshold value σ_w1=95.4%;

2) can calculate from table and obtain, wedge shape W₄₀Drop on the hit rate P of [-30 μm, 30 μm]_w2=96.92%, set hit rate threshold value σ_w2=95.4%;

3) can calculate from table and obtain, wedge shape W₄₀Variance P_w3=6.99 μm, set wedge shape variance threshold values σ_w3=10 μm;

Can obtaining according to wedge shape grade decision rule, the result of calculation of measured data is unsatisfactory for Grade A standard: P_w1>σ_w1And P_w3<σ_c3, but meet goods of inferior quality standard: it is unsatisfactory for Grade A standard, P_w2>σ_w2, judge to obtain this cold rolling base as goods of inferior quality by wedge shape grade for this.

Step 4: judging to judge with wedge shape grade in conjunction with convexity and local high spot grade, taking both the lowest class is principle, and obtaining cold rolling base cross section quality synthetic determination result is goods of inferior quality, meets following criterion:

If convexity and local high spot judge grade: Grade A, wedge shape judges grade: goods of inferior quality, then synthetic determination grade: goods of inferior quality.

Claims (1)

1. the cross section quality decision method of a cold rolling base, it is characterised in that described method comprises the steps of:

Step 1: obtain cold rolling base total length cross section quality data from section instrumentation, including distance edge 40mm place convexity C₄₀, distance edge 40mm place wedge shape W₄₀, local high spot H_s;

Step 2: set convexity desired value C_A, convexity tolerance interval C, C=15 μm-20 μm; Carry out convexity and local high spot according to measured data in conjunction with following condition to judge:

2.1 calculate convexity C₄₀Drop on [C_A-C,C_A+ C] interval hit rate P_c1, set hit rate threshold value σ_c1, σ_c1=95.4%;

2.2 calculate convexity C₄₀Drop on [C_A-C,C_A+ 2C] hit rate P_c2, set hit rate threshold value σ_c2, σ_c2=95.4%;

2.3 calculate convexity C₄₀Variance P_c3, convexity variance threshold values scope σ_c3=8-10 μm;

2.4 obtain local high spot meansigma methods H_{s_avg}, local high spot threshold range σ_c4=15-20 μm;

2.5 convexitys and local high spot grade decision rule:

Grade A standard: P_c1>σ_c1And P_c3<σ_c3,H_{s_avg}<σ_c4;

Goods of inferior quality standard: be unsatisfactory for Grade A standard, but P_c2>σ_c2And H_{s_avg}<σ_c4;

Defective standard: be unsatisfactory for Grade A or goods of inferior quality standard;

Step 3: set wedge shape desired value W_A, W, W=15 μm-20 μm of wedge tolerance interval, carry out following wedge shape judgement according to measured data:

3.1 wedge shape W₄₀Drop on [W_A-W,W_A+ W] hit rate P_w1, set hit rate threshold value σ_w1, σ_w1=95.4%;

3.2 wedge shape W₄₀Drop on [W_A-1.5W,W_A+ 1.5W] hit rate P_w2, set hit rate threshold value σ_w2, σ_w2=95.4%;

3.3 wedge shape W₄₀Variance P_w3, wedge shape variance threshold values σ_w3=8-10 μm;

3.4 wedge shape grade decision rules:

Grade A standard: P_w1>σ_w1And P_w3<σ_w3;

Goods of inferior quality standard: be unsatisfactory for Grade A standard, P_w2>σ_w2;

Defective standard: be unsatisfactory for Grade A or goods of inferior quality standard;

Step 4: judging to judge with wedge shape grade in conjunction with convexity and local high spot grade, taking both the lowest class is principle, obtains cold rolling base cross section quality synthetic determination result as follows:

1) if convexity and local high spot judge grade: Grade A, wedge shape judges grade: Grade A, then synthetic determination grade: Grade A;

2) if convexity and local high spot judge grade: Grade A, wedge shape judges grade: goods of inferior quality, then synthetic determination grade: goods of inferior quality;

3) if convexity and local high spot judge grade: Grade A, wedge shape judges grade: defective, then synthetic determination grade: defective;

4) if convexity and local high spot judge grade: goods of inferior quality, wedge shape judges grade: Grade A, then synthetic determination grade: goods of inferior quality;

5) if convexity and local high spot judge grade: goods of inferior quality, wedge shape judges grade: goods of inferior quality, then synthetic determination grade: goods of inferior quality;

6) if convexity and local high spot judge grade: goods of inferior quality, wedge shape judges grade: defective, then synthetic determination grade: defective;

7) if convexity and local high spot judge grade: defective, wedge shape judges grade: Grade A, then synthetic determination grade: defective;

8) if convexity and local high spot judge grade: defective, wedge shape judges grade: goods of inferior quality, then synthetic determination grade: defective;

9) if convexity and local high spot judge grade: defective, wedge shape judges grade: defective, then synthetic determination grade: defective.