35 results about "Continuous cooling transformation" patented technology

The invention provides a method for formulating a water-air alternate time-controlled quenching process. The method comprises the following steps of: step 1, predicating a structure composition of a part with required performance according to the performance detection part of an alloy steel piece and specific performance requirements; step 2, according to the super-cooled austenite isothermal cooling transformation curve or the super-cooled austenite continuous cooling transformation curve of a material, acquiring the longest cooling time or the minimum cooling speed which the structure needs to reach a certain temperature; step 3, dividing an alloy steel piece into a cooling speed control area and a slow cooling area along a section from the surface to the centre; step 4, determining the water-air alternation times of the cooling speed control area, and a water-cooling time and an air-cooling time each time; and step 5, determining the water-air alternation times of the slow cooling area, and a water-cooling time and an air-cooling time each time. With the adoption of the method provided by the invention, the alloy steel piece can obtain required performance or structure on the premise of avoiding cracking; and the method is suitable for a quenching treatment for the alloy steel pieces with various ingredients.

The invention provides a method for controlling generation of a cold crack in the welding process based on electromagnetic induction heating, relating to a method for controlling generation of the cold crack in the welding process. The invention aims to solve the problems that a welding seam and crystal grains in a heat influence region become coarse and the metal toughness is lowered due to using a pre-welding pre-heating method for preventing generation of the cold crack and the problems of difficult control of flame power, easy surface overburning, welding seam surface state change and welding production procedure increase in a post-welding heat treatment method in the traditional welding process. The method comprises the following steps of searching a welding continuous cooling transformation curve corresponding to special welding materials; determining a workpiece to be welded; welding a temperature field on the surface; determining induction heating process parameters; welding frock; and implementing welding until welding finish. The invention is used for welding.

The invention discloses a method of measuring a large deformation resistant pipeline steel SH-CCTA curve, which is a simulated HAZ continuous cooling transformation curve. According to the method, welding conditions are simulated to heat a sample; a CCT dilatometer is used to measure the critical points (Ac1 and Ac3), expanding curves under different cooling speeds are measured; a tangent method is used to determine the temperature of a phase transformation point under different cooling speeds; a metallographic method under the assistance of a hardness method is used to analyze and determine a room temperature tissue; and finally a complete SH-CCT curve is drawn. On one aspect, the method can be used to evaluate the welding property of steel or predict the tissue and performance of welding heat affected zone; and on the other aspect, a technical reference is provided for designing a proper welding technology, in particular, welding line energy.

The invention discloses a measuring method of an aluminum alloy CCT (Continuous Cooling Transformation) diagram, which comprises the following steps: 1. measuring data of aluminum alloy voltage and temperature along with the change of time under various cooling regimes; 2. drawing a voltage-temperature curve and a temperature-time curve in the cooling process of a sample according to the data obtained by the first step; 3. determining phase transformation points: determining the temperatures of phase transformation starting points and phase transformation ending points of the aluminum alloy sample according to the change position of the slope of the voltage-temperature curve; and 4. drawing the CCT diagram: drawing the temperature-time curve of the sample obtained at different cooling speeds to a logarithmic coordinate system, labeling the phase transformation starting points and the phase transformation ending points on corresponding temperature-time curves according to the phase transformation starting points and the phase transformation ending points determined according to the voltage-temperature curve, and connecting the phase transformation starting points and the phase transformation ending points by lines to obtain the CCT diagram of the sample alloy. The method has the advantages of strong operability, simple process, simple operation, high speed, dense acquired points, measuring material saving and higher measuring precision, fills up the blank of a measuring technology of the CCT diagram of the aluminum alloy and is suitable for scientific research units to measure the phase transformation points of the aluminum alloy and the CCT diagram.

The invention relates to a method for measuring an aluminum alloy continuous cooling transformation curve, and belongs to the technical field of non-ferrous metal material preparation. According to the method provided by the invention, by recording the change of thermal equivalents in different temperature intervals, precipitation temperature intervals of quenching reaction in a quenching process are distinguished based on the change of the thermal equivalents. The method provided by the invention measures exothermic reaction of aluminum alloy in the quenching process by applying a differential scanning calorimetry (DSC), and combines with microstructure analysis and mechanical property testing, so as to obtain the aluminum alloy continuous cooling transformation curve. Compared with other methods, the method provided by the invention can distinguish initial and final temperatures of different quenching-induced precipitated phases based on accurate cooling curves in certain cooling intervals. The continuous cooling transformation curve obtained by the method provided by the invention has the advantages of high precision, great guiding significance and the like.

The invention discloses a method for linkage production of high-toughness pipeline steel by adopting jetting and laminar cooling, belonging to the technical field of production of medium-thickness plates. The super-cooled austenite continuous cooling transformation (CCT) curve of a steel plate is measured according to the chemical constituents of the steel plate. The steel plate comprises the following chemical ingredients in percentage by weight: 0.045-0.075 percent of C, 0.1-0.3 percent of Si, 1.55-1.85 percent of Mn, 0.045-0.085 percent of Nb, 0.1-0.2 percent of Mo, 0.1-0.3 percent of Ni, 0.01-0.02 percent of Ti and the balance of Fe and inevitable impurities. The method has the advantages that the problems of low toughness of pipeline steel plates of over grade X80 produced by jet cooling and low strength of pipeline steel plates of over grade X80 produced by laminar cooling are solved, and the high-toughness pipeline steel is produced.

The invention is suitable for the field of low temperature rolling, and provides a control method of a rod and wire production line temperature control rolling process. The method comprises the steps of determining a critical phase change temperature and a critical cooling speed of a rolled piece generation phase change tissue according to the a steel type and a corresponding continuous cooling transition curve characteristic; calculating the water cooling time according to a length value of a water tank and a rolling speed of a rolled piece, and calculating a corresponding maximum water flow rate at the critical phase change temperature and the critical cooling speed according to the water cooling time and the cooling water temperature; acquiring an initial value of the water flow rate within the maximum water flow rate range; calculating a uniform temperature of the rolled piece according to a heat transfer relation of each node of the rolled piece; judging an absolute difference value of the uniform temperature and a target temperature to exceed a first preset threshold value, adjusting the water flow rate, re-calculating the uniform temperature, and calculating the water flow rate which cannot satisfy the first preset threshold value. By adopting the control method, the automatic derivation of process parameters in the temperature control rolling process can be realized, and the low efficiency and inaccuracy for a traditional method for referring to the existing engineering or experience in the prior art can be overcome.

The invention discloses production method for rapidly cooling a medium plate after rolling, belonging to the technical field of production of medium plates. The method comprises the following process steps of: adjusting an ultrafast cooling (UFC) frame to 300mm+h till the cross point between extension lines of upper and lower nozzles of equipment is positioned on the central line of a steel plate; during ultrafast cooling, setting cooling rules and parameters according to the steel kind, specification as well as required final cooling temperature and cooling speed of the steel plate; startingmiddle spraying, side spraying and air blowing to remove residual water from the surface of steel plate to increase the cooling uniformity, starting UFC equipment, and spraying water onto the steel plate with a gap nozzle and a ganged nozzle for cooling; and controlling the cooling speed and cooling termination point according to the CCT (Continuous Cooling Transformation) curve of steel, whereinthe cooling speeds of steel plates of different thicknesses are 5-80 DEG C/s, and the final cooling temperature is controlled at 450-800 DEG C. The method has the advantages: by controlling the cooling process of the steel plate after rolling, control over phase change and organization is realized, and the aim of enhancing the roughness of the steel plate is fulfilled.

The invention relates to a preparation method of manganese series water quenching bainitic steel, which belongs to the technical field of alloy steel preparation. First, the steel is smelted by a conventional steel smelting process, teemed or continuously cast and produced; the weight percentage of all components in the steel is as follows: C: 0.05 percent to 0.42 percent, Mn: 1.80 percent to 3.00 percent, Si: 0.20 percent to 1.80 percent, Cr: 0 percent to 1.60 percent, and the rest is Fe; after forge rolling, the steel is directly cooled by water or oil; and then, the steel is heated to 200 DEG C to 650 DEG C, and tempered after the temperature is preserved for 1h to 3h. In the preparation method, the alloying of an appropriate amount of Mn, Si, Cr and other elements changes the continuous cooling conversion curve of the steel grade, improves the hardenability characteristic of the steel and obtains components with good obdurability. The product produced by the preparation method has excellent performance, simple process and low cost.

The invention relates to a method for thinning a crystalline grain of a large low alloy cast based on computer simulation, material continuous cooling transformation curve measurement and material phase change mode control, and belongs to the field of steel and iron metallurgy. The method comprises the steps as follows: firstly, measuring a continuous cooling curve of a related cast material and determining the critical cooling rate of the material with martensite, bainite and pearlite phase change; secondly, building a corresponding cast model, and determining the cooling rate of the parts of the cast under different cooling mediums by a way of computer simulation; and lastly, heating the cast to be A3<+> (30-80 DEG C) for austenitizing at first, slowly cooling to be room temperature, enabling the cast to be subjected to diffusion or semi-diffusion phase change, after that, heating the cast to be A3<+> (30-50 DEG C) for austenitizing, selecting a proper cooling way according to simulation calculation, enabling the cast to be subjected to bainite phase change, and thinning the crystalline grain of the cast to be below the ASTM (American Society for Testing Material) standard crystalline grain size 7.5 through the semi-diffusion bainite phase change.

The invention is suitable for the field of bar online thermal treatment and discloses a control method for controlling cooling process in a bar production line. The method comprises the following steps: determining a critical phase-transition temperature and a critical cooling speed of a martensite generated on the surface of the rolled piece according to the steel type M and the corresponding continuous cooling transformation curve; calculating the corresponding minimum water flow Qmin when reaching the critical phase-transition temperature and the critical cooling speed; determining a water flow initial value Q according to the Qmin; according to the water flow initial value Q, calculating the thickness of the martensite generated after finishing the quenching stage through the finite-discrete scheme to obtain the required martensite thickness; and calculating to obtain the finial water flow zone Qm which satisfies the martensite thickness. By adopting the method, the technological parameters of the controlling cooling process can be automatically deduced; compared with the mode of copying or referring to the operated production line in the prior art, the method is more effective and accurate.

Disclosed is a test method for a welding CCT diagram of a resistance type thermal simulation test machine. The test method includes the steps of heating a thermal simulation sample from the room temperature to the peak temperature Tp; staying for one second; subjecting the sample to linear cooling in three stages, wherein the first cooling stage is the cooling from the peak temperature Tp to 1000 DEG C, the second cooling stage is the cooling from 1000 DEG C to 800 DEG C, and the third cooling stage is the cooling from 800 DEG C to the room temperature; accurately identifying the start and end points of the phase transition on a thermal expansion curve according to a tangent method. The test method for the welding CCT diagram of the resistance type thermal simulation test machine takes the problems of heating rate, multi-stage linear cooling and temperature overshoot into overall consideration, so that the tested welding CCT diagram is close to the actual welding thermal cycle, and the measured phase transition points are accurate. The test method is applicable to the test of the welding of CCT on all resistance type thermal simulation test machines.