CN103170511A - Measurement method for hot rolling strip steel laminar cooling water temperature - Google Patents

Abstract

The invention provides a measurement method for hot rolling strip steel laminar cooling water temperature. Thermal resistors are respectively arranged in a 2# laminar cooling water tank and a 5# laminar cooling water tank. An analog to digital (A/D) conversion module and two temperature transmitters are configured in a programmable logic controller (PLC) control cabinet. When a threading bites steel, the temperature transmitters transmit an analog current signal to the A/D conversion module, and a central processing unit (CPU) of the PLC reads a digital signal and outputs the actual temperature of spot laminar cooling water. Due to the fact that the output timing sequence of the actual water temperature and calculation timing sequence of a laminar automatic control system are synchronous, accurate data of the actual water temperature can be supplied to the laminar automatic control system, and accordingly a hit rate of temperature control accuracy of strip steel coiling process is improved by more than 0.5%, uniformity of product performance of strip steel is improved, and a qualified rate of the product performance is improved.

Description

A kind of TEMPERATURE FOR HOT STRIP LAMINAR coolant water temperature measuring method

Technical field

The invention belongs to steel rolling characterization processes field, relate in particular to a kind of measuring method for the TEMPERATURE FOR HOT STRIP LAMINAR coolant water temperature.

Background technology

It is the key factor that affects the hot-strip product performance index that hot-strip batches temperature, and its control accuracy directly affects tissue and the mechanical property with steel.The scope that exceeds requirement when actual coiling temperature, the performance meeting variation of coil of strip, so guarantee that hot-strip batches the target temperature range that temperature reaches regulation, improve control precision of coiling temperature is the major issue of hot continuous rolling field concern always.

Laminar Flow Controling Cooling System of Hot-rolled Strip is the most frequently used Strip Steel Coiling Temperature control system of present hot rolling industry, this system architecture is very complicated, and it relates to many-sided problems such as the institutional framework of laminar flow water temperature, belt steel temperature, speed, thickness, rolled piece inside and phase transformation.From control angle, have typical multivariable, non-linear, strong coupling feature, because batching temperature controlled development, hot-strip passed through a long time.From eighties of last century sixties, the laminar model research staff begins analytic sheaf flowing water temperature, belt steel temperature, speed etc. affects the factor that coiling temperature is controlled, and after applying it to the laminar flow cooling control model, it is controlled effect qualitative leap has occured.

Through retrieval, CN102284511A provides " a kind of band steel laminar flow chilling temperature adaptive approach ", CN102397887A discloses a kind of " inhibiting band steel is in the method for the cooling middle afterbody temperature fluctuation of laminar flow ", CN101456038 provides a kind of " plate-belt temperature monitoring method during hot-rolled strip steel stream cooling process ", but the common defects of said method is all to have ignored the impact that the laminar flow water temperature is controlled Strip Steel Coiling Temperature, thereby when water temperature changes, will inevitably cause temperature control precision to reduce.The small part control system adopts the theoretical method of calculating water temperature to participate in laminar model and calculates, although control precision of coiling temperature can improve to some extent, but when rolling line stops rolling or variation of ambient temperature when obvious, theoretical calculating also relatively large deviation can occur, control precision of coiling temperature reduces equally, and and then causes the properties of product lack of homogeneity.

Summary of the invention

Purpose of the present invention aim to provide a kind of can be for automatic Laminar Cooling Control System provides actual water temperature data accurately, thereby improve the TEMPERATURE FOR HOT STRIP LAMINAR coolant water temperature measuring method of Strip Steel Coiling Temperature control accuracy and properties of product qualification rate.

For this reason, the technical solution taked of the present invention is:

A kind of TEMPERATURE FOR HOT STRIP LAMINAR coolant water temperature measuring method is characterized in that:

In second and last laminar cooling water case, a thermal resistance is set respectively, thermal resistance is arranged at apart from 190-210mm place, laminar cooling water case bottom surface;

At PLC switch board configuration A/D modular converter; 2 dc sources and temperature transmitter are installed simultaneously;

Thermal resistance connects temperature transmitter by control cables, and the temperature transmitter output is connected with the A/D modular converter;

In the Rolling Production process, the actual water temperature output timing is got second finishing mill and is stung steel signal and laminar flow automatic control system calculating timing synchronization, namely when second finishing mill threading stung steel, temperature transmitter will convert current analog signal to from the observed temperature signal that thermal resistance receives and flow to the A/D modular converter, the A/D modular converter converts current analog signal to data signal, CPU by PLC reads data signal, and exports the cooling cooling water actual temperature of on-the-spot laminar flow.

Beneficial effect of the present invention is:

Due to actual water temperature output timing of the present invention and laminar flow automatic control system calculating timing synchronization, therefore can provide actual water temperature data accurately for automatic Laminar Cooling Control System, thereby improve Strip Steel Coiling Temperature control accuracy hit rate more than 0.5%, make with the properties of product uniformity of steel and improve, the properties of product qualification rate improves.

The specific embodiment

Take seven finishing mills of F1-72, five laminar cooling water casees of 1#-5# as example, particular content and the control procedure of its TEMPERATURE FOR HOT STRIP LAMINAR coolant water temperature measuring method are:

A calibration is installed respectively in 2# and 5# laminar cooling water case number is the industrial heat resistance of Pt100, the particular location that thermal resistance arranges is apart from 2# and 200mm place, 5# laminar cooling water case bottom surface, and fixes with angle steel.The particular location of thermal resistance setting is directly connected to accuracy and the stability of temperature measurement.

Installing 2 in the PLC switch board, to be input as Pt100, output 0-10V, 24V dc source, range be the temperature transmitter of 0-60 ℃; Simultaneously, A/D modular converter that current conversion is become data signal of configuration.

Its connected mode is: by control cables, thermal resistance is connected on temperature transmitter, the temperature transmitter output is connected with the A/D modular converter.

in the Rolling Production process, the actual water temperature output timing is got sting steel signal and the laminar flow automatic control system of second finishing mill F2 and is calculated timing synchronization, when the F2 threading is stung steel, temperature transmitter will convert current analog signal to from the observed temperature signal that thermal resistance receives and flow to the A/D modular converter, the A/D modular converter converts current analog signal to data signal, CPU by PLC reads data signal, and export the cooling cooling water actual temperature of on-the-spot laminar flow, the Measurement accuracy of realization to the cooling actual water temperature of TEMPERATURE FOR HOT STRIP LAMINAR, thereby for automatic Laminar Cooling Control System provides actual water temperature data accurately.

Claims (1)

1. TEMPERATURE FOR HOT STRIP LAMINAR coolant water temperature measuring method is characterized in that:

In second and last laminar cooling water case, a thermal resistance is set respectively, thermal resistance is arranged at apart from 190-210mm place, laminar cooling water case bottom surface;

Configuration A/D modular converter in the PLC switch board; 2 dc sources and temperature transmitter are installed simultaneously;

Thermal resistance connects temperature transmitter by control cables, and the temperature transmitter output is connected with the A/D modular converter;

In the Rolling Production process, the actual water temperature output timing is got second finishing mill and is stung steel signal and laminar flow automatic control system calculating timing synchronization, namely when second finishing mill threading stung steel, temperature transmitter will convert current analog signal to from the observed temperature signal that thermal resistance receives and flow to the A/D modular converter, the A/D modular converter converts current analog signal to data signal, CPU by PLC reads data signal, and exports the cooling cooling water actual temperature of on-the-spot laminar flow.