The surface temperature of hot-rolled round bar is high, the radiation intensity is strong, and there are phenomena such as water and iron oxide scale, which are very different from the surface of cold-rolled round bar. The profiler uses four two-dimensional laser measuring sensors to detect the surface defects of round bar, and can detect both cold and hot rolling.
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According to the characteristics of the hot-rolled round bar surface, a new defect detection and recognition algorithm process is proposed. By adopting a high-strength purge mode, a large amount of water and oxide scale in the measurement area are removed, so that the false defects caused by it are eliminated, and the defect inspection is guaranteed. At the same time, it reduces the misrecognition rate of defects. Through online application, this method can meet the requirements of online inspection, and the detection rate and recognition rate of defects are both very high, which meets the inspection requirements.
As a defect detection equipment, the contour measuring instrument can detect the folding, warping, pits, grooves, lugs and other defects on the surface of round bar in real time, and give out-of-tolerance alarms. Because it is an online detection device, it can be used for rolling Defects in each part of the material are detected, thereby reducing the possibility of missed inspections.
The profile measuring instrument has a large detection range, which can detect rolled materials within the range of 0~200mm. At the same time, the measurement range can be customized according to requirements. It can identify defects as small as 0.5mm and improve the detection effect of defects.
The profile measuring instrument is an intelligent non-destructive online defect detection device that comprehensively evaluates the surface quality of round bar and helps operators effectively control the production process. Defect data can be automatically archived, screen displayed, stored and alarmed. It can be applied to the defect detection of various long products.
Regardless of whether it is hot-rolled or cold-rolled round bar, the outer diameter and ovality are important data to be tested. On-line testing is the current mainstream testing method. Let's take a look at the round bar diameter gauge.
In order to easily know whether the round bar is qualified in production, and to adjust the rolling mill in time, in order to obtain the inspection data of each position of the whole rolled material, in order to quickly obtain the inspection chart, the detection of the outer diameter of the round bar adopts eight-axis intelligent measurement. Diameter.
When measuring, set the basic parameters of the round bar to be tested: name, nominal value, etc. If the measured value exceeds the tolerance, an audible and visual alarm will be issued, and the operator will adjust the rolling mill in time. In addition, the detection data can be transmitted to the control system in real time for high-quality production.
Fundamental:
The measured object is irradiated by the processed parallel light field of view to form a shadow with a clear boundary and exactly the same as the outer diameter of the measured object. The small hole imaging is used to form an enlarged or reduced real image, and the outer diameter is calculated by the linear CCD chip.
Detection method:
The single-axis probe is far from meeting the requirements for round bar inspection. In order to obtain a complete cross-section and accurate ellipticity, a uniformly distributed eight-axis probe is used for testing. This detection method has a small blind area. The twisting pendulum can be detected when encountering small bumps, which is an important equipment for completing round bar detection.
measurements per second, with a detection accuracy of 0.02mm, which meets the current inspection requirements for round bar. For round bar within 30mm, the measurement accuracy can reach 0.01mm.
Reliable operation in a variety of harsh steel rolling environments, high stability, high precision, unattended, remote display, sound and light alarm prompts when encountering problems.
IP54 protection level, with anti-interference and other protection measures, is not affected by rolling material jitter, and the equipment runs stably.
The hardware and software are all independently designed and can be customized according to needs. After-sales service is guaranteed.
It is not affected by the environment such as high temperature and water mist, and has a cooling and dust-proof system that combines air-cooling and water-cooling;
It is not affected by the iron oxide scale and can be purged of the iron oxide scale;
Not affected by the size of the rolled material, the measurement range can be customized;
Not affected by jitter, multiple ways to prevent the impact of jitter;
Not affected by the temperature of the rolled material, it can be applied to the detection of high-temperature rolled material at around &#;;
Unaffected by the material of the rolled material, non-contact detection.
round bar mainly provides tensile properties and cannot have cracks, but cracks are prone to occur during round bar rolling. Let&#;s look at the causes and countermeasures of cracks, and more importantly, how to monitor cracks.
Cause Analysis
The surface crack defects of round bar are mainly related to the smelting and rolling process.
When there is a problem in casting, it is easy to cause core cracks and subcutaneous bubbles; when the pulling speed is not appropriate, it is easy to form surface and core cracks. These defects will extend to the surface with the reduction of the section of the rolled piece during the rolling process, forming surface cracks.
Improper rolling process can also easily produce surface cracks and can expand cracks caused by smelting. If the rolling process is better, it can not only avoid cracks in the rolling process, but also eliminate the defects caused by part of the smelting process.
solution
round bar rolling is usually reduced by the following methods to improve the heating quality of the billet, and the temperature is uniform; modify the pass, change the hexagonal-square pass into an elliptical-round pass; change the structure of the blooming roll to reduce micro cracks.
Improve the quality of steelmaking and reduce the impurity content; optimize the rolling process, especially the heating process, set the material type reasonably, prevent the occurrence of ears during rolling, etc., perform anti-scratch treatment, and appropriately increase the width of the rolling mill exit guide groove Wait.
Strengthen the maintenance of cold shear, change the shear mode, increase the shear temperature, and control the temperature above 400&#; to effectively reduce the shear cracks.
The steel is slowly cooled to eliminate center segregation.
The surface cracks of round bar are diverse, and regardless of the steel grades and specifications, cracks are likely to occur. Moreover, due to the adhesion of oxide scale on the surface of the round bar, surface cracks are detected by surface pickling and hot upsetting. To this end, it is necessary to develop a device that eliminates the oxide scale for defect detection.
The profile measuring instrument can perform on-line detection and is suitable for high-temperature rolling. It is equipped with a cooling and dust-proof detection device and a high-pressure blower to forcefully blow away the oxide scale surrounding the surface of the round bar. The detection can be completed at the hot rolling position , And not only detect surface crack information, but also detect a variety of surface defects.
The full coverage measurement mode of the profile measuring instrument enables the equipment to perform qualitative and quantitative detection of defects such as folding, warping, pits, grooves, and lugs on the surface of the rolled material.
After improving the production process, although the occurrence of cracks has been greatly reduced, the necessary inspection measures are indispensable, especially on-line inspection, so that the location and time of the defect can be found in time, and the machine can be shut down in time to adjust and control to reduce unqualified Production of products.
The profile measuring instrument detects the size of defects quickly and accurately. At present, it can detect the information of defects of 0.5mm and above, which is a check on the quality of round bar production.
In addition to the profiler, there are many online inspection equipment that can be used in the production of round bar, such as smart diameter gauges to measure outer diameter and ovality, straightness gauges to measure diameter and straightness, etc.
In short, the goal of measuring instruments is to detect quality in time and bring high-quality rolling. Cracks in round bar are not terrible, as long as timely monitoring and adjustment of the process can produce high-quality round bar.
Classified by process
round bar is divided into three types: hot rolled, forged and cold drawn. The specification of hot-rolled round bar is 5.5-250 mm. Among them: 5.5-25mm small round bar is mostly supplied in straight strips, which are often used as steel bars, bolts and various mechanical parts; round bar larger than 25mm is mainly used to manufacture mechanical parts and tube blanks for seamless steel pipes. Wait.
Classified by chemical composition
Carbon steel can be divided into low carbon steel, medium carbon steel and high carbon steel according to its chemical composition (that is, carbon content).
(1) Mild steel
Also known as mild steel, mild steel with carbon content ranging from 0.10% to 0.30% is easy to accept various processing such as forging, welding and cutting. It is often used to make chains, rivets, bolts, shafts, etc.
(2) Medium carbon steel
Carbon steel with a carbon content of 0.25% to 0.60%. There are many products such as killed steel, semi-killed steel, rimmed steel and so on. In addition to carbon, it can also contain a small amount of manganese (0.70% to 1.20%). According to product quality, it is divided into ordinary carbon structural steel and high-quality carbon structural steel. Good thermal processing and cutting performance, but poor welding performance. Strength and hardness are higher than low carbon steel, while plasticity and toughness are lower than low carbon steel. Hot-rolled and cold-drawn materials can be used directly without heat treatment, or they can be used after heat treatment. The quenched and tempered medium carbon steel has good comprehensive mechanical properties. The highest hardness that can be achieved is about HRC55 (HB538), and σb is 600&#;MPa. Therefore, among the various uses of medium strength level, medium carbon steel is the most widely used. In addition to being used as a building material, it is also widely used to manufacture various mechanical parts.
(3) High carbon steel
Often called tool steel, the carbon content ranges from 0.60% to 1.70%, which can be hardened and tempered. Hammers, crowbars, etc. are made of steel with a carbon content of 0.75%; cutting tools such as drills, taps, and reamers are made of steel with a carbon content of 0.90% to 1.00%.
Classified by steel quality
According to the quality of steel, it can be divided into ordinary carbon steel and high-quality carbon steel.
(1) Ordinary carbon structural steel, also known as ordinary carbon steel, has wider restrictions on carbon content, performance range, and phosphorus, sulfur and other residual elements. In China and some countries, it is divided into three categories according to the guarantee conditions of delivery: Class A steel (Class A steel) is a steel that guarantees mechanical properties. Class B steel (Class B steel) is a steel with guaranteed chemical composition. Special steel (C steel) is a steel that guarantees both mechanical properties and chemical composition, and is often used to manufacture more important structural parts. The most produced and used in China is A3 steel (Class A No. 3 steel) with a carbon content of about 0.20%, which is mainly used for engineering structures.
Some carbon structural steels also add a small amount of aluminum or niobium (or other carbide forming elements) to form nitride or carbide particles to limit the growth of grains, strengthen the steel, and save steel. In China and some countries, in order to meet the special requirements of professional steel, the chemical composition and performance of ordinary carbon structural steel have been adjusted, thereby developing a series of professional steel of ordinary carbon structural steel (such as bridges, buildings, Steel bars, steel for pressure vessels, etc.).
(2) Compared with ordinary carbon structural steel, high-quality carbon structural steel has a lower content of sulfur, phosphorus and other non-metallic inclusions. According to the different carbon content and use, this type of steel can be roughly divided into three categories:
&#; Less than 0.25%C is low carbon steel, especially 08F, 08Al with carbon content less than 0.10%, etc., because of its good deep drawability and weldability, it is widely used as deep drawing parts such as automobiles and can making &#;&#;Wait. 20G is the main material for making ordinary boilers. In addition, low carbon steel is also widely used as carburizing steel for machinery manufacturing.
&#;0.25&#;0.60%C is medium carbon steel, which is mostly used in quenched and tempered state to make parts for machinery manufacturing industry.
&#;High carbon steel greater than 0.6% C is used to make springs, gears, rolls, etc.
According to the different manganese content, it can be divided into two steel groups with ordinary manganese content (0.25-0.8%) and higher manganese content (0.7-1.0% and 0.9-1.2%). Manganese can improve the hardenability of steel, strengthen ferrite, and increase the yield strength, tensile strength and wear resistance of steel. Usually, &#;Mn&#; is added after the grade of steel with high manganese content, such as 15Mn, 20Mn, to distinguish it from carbon steel with normal manganese content.
According to the purpose, it can be divided into carbon structural steel and carbon tool steel.
Carbon tool steel has a carbon content of between 0.65 and 1.35%. After heat treatment, high hardness and high wear resistance can be obtained. It is mainly used to manufacture various tools, cutting tools, molds and measuring tools (see tool steel).
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Carbon structural steel is divided into 5 grades according to the yield strength of steel:
Q195, Q215, Q235, Q255, Q275
Each grade is divided into grades A, B, C, and D due to different quality. There are four at most, and some have only one. In addition, there are differences in deoxidation methods for steel smelting.
The difference between round bar and other steel bars:
1. The appearance is different. The round bar has a smooth appearance, no grains and no ribs. Other steel bars have engraved or ribbed appearances on the surface. This results in a small bonding force between the round bar and concrete, while other steel bars and concrete Great adhesion.
2. The composition is different. round bar (first-grade steel) belongs to ordinary low-carbon steel, and most other steel bars are alloy steel.
3. The strength is different, the strength of round bar is low, and the strength of other steels is high, that is, round bar with the same diameter is compared with other steel bars, the tensile force that round bar can withstand is smaller than other steel bars, but the plasticity of round bar is better than other steel bars. Strong, that is, the round bar has a larger deformation before being broken, and the deformation of other steel bars is much smaller before being broken.
We offer many types of measurement instruments for the steel manufacturing industry. If you have requirements for intelligent measurement of diameter, length, thickness, etc for your steel products, we will always find a solution for you.
This model of equipment is mainly used for online size detection of hot-rolled anchor steel and rebar production lines.
1) The measurement is accurate, and the dynamic error of measuring round steel is not more than 0.01mm. The dynamic error of the rebar is not more than 0.06mm.
2) The unique jitter error elimination technology eliminates the measurement error caused by the jitter of the rolling material.
3) Fully digital high-frequency measurement system, the measurement frequency is as high as Hz, that is, rolled sections are measured per second
4) It can detect the common defects of round steel, such as: &#;ear&#;, &#;wrong roll&#;, etc.
5) Measurement data alarm function.
6) Historical data queries can be provided.
The diameter measuring instrument has 3 built-in industrial cameras, which can take images from different angles by using the self-illumination of anchor rods and rebars during hot rolling and using the backlight to take clear images during cold rolling. It can measure the inner diameter, outer diameter, rib height, pitch, and other characteristic dimensions of the rolled material.
Anchor steel inner diameter d0, anchor steel outer diameter d1; anchor steel diagonal dimensions d2, d3;
Pitch p, relative offset dimension of transverse ribs on both sides p/2
Parameters such as product specifications, and positive and negative tolerances can be set;
You can set the faulted channel, communication port, thermal expansion coefficient, etc.;
For data records, the storage time is more than 1 year; for historical data queries, the size at a certain moment can be queried, and the time is accurate to the second.
The form and threshold of over-tolerance and over-temperature alarms can be set;
Automatic/manual, calibrate after inputting the thermal expansion coefficient.
Related data color warning and buzzer sound alarm in the main control room; on-site LED display data color and status display alarm.
Measure the temperature sensor in the car, when the temperature in the car exceeds the temperature range of the camera, the alarm light in the main control room will light up and alarm; the on-site LED display status will display the alarm.
The equipment is mainly used for online size detection of hot-rolled anchor steel and rebar production lines.
(mm)
rolling diameter(mm)
Measurement accuracy(mm)
Repeatability(mm)
Measurement frequency(frame/s)
DimensionsL×W×H
Weight (KG) JX03-DG35 0-35 6-25 ±0.06 0.02 50 ×800× 200 JX03-DG50 0-50 6-40 ±0.06 0.02 25 ×800× 240
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