Low-temperature Heat Research Articles

Dynamic performance analysis of a new low-temperature nuclear heating system with APROS

ABSTRACT Pool-type low-temperature heating reactor (PLTHR) has attracted considerable attention throughout the world due to its low operating parameters and satisfactory inherent safety in district heating. Exploring the dynamic performance of PLTHR is a prerequisite for designing control systems and developing operation strategies. Until now, the dynamic performance of the district heating system using a 400 MW pool-type low-temperature heating reactor (DHR-400) has not been fully discussed. Based on APROS software, a precise dynamic model for DHR-400 is constructed in this paper. The dynamic responses of DHR-400 under five external variables such as control rod reactivity, first loop flow rate, second loop flow rate, third loop flow rate, and return temperature at the third loop are investigated. The results revealed that the core power variation is not linear with the flow rate variation at the three loops. Core power variations are −16.27, −14.04, and −20.96 MW with a 30% reduction in flow rate at the first loop, the second loop, and the third loop, respectively. Considering safe operation, when there are minor fluctuations in the heating demand, the core power regulation method by adjusting the third loop’s flow rate should be given priority without altering the position of the control rods.

Numerical analysis of scroll compressor performance with pre-discharge valve for low-temperature heat pumps

Scroll compressors are a crucial component of automotive air conditioning systems. When operating at off-designed working conditions, over-compression can occur in the scroll compressor. A pre-discharge valve (PDV) is proposed to enhance the performance of the scroll compressor under off-design working conditions. The performance of the scroll compressor with a PDV for a low-temperature heat pump system is simulated. The results show that the scroll compressor with the PDV structure has lower pressure in the compression chambers and improved over-compression compared to conventional scroll compressors. The use of the PDV also leads to a reduction in the temperature of the refrigerant gas in the compression chambers and a decrease in the leakage between the compression chambers. As the evaporating temperature increases from −25 °C to −5 °C, the mass flow rate and volumetric efficiency increase, and the discharge temperature decreases. At an evaporating temperature of −5 °C, the discharge temperature at the center discharge port of the scroll compressor with the PDV is reduced by 2.4 °C compared to the conventional scroll compressor. The input power of the scroll compressor is reduced by 165.4 W–897.7 W. The volumetric efficiency and the isentropic efficiency are improved by 0.13 % and 6.63 % respectively.

Proposal of a novel multi-generation system based on dual-loop absorption power and compression refrigeration cycle

One of the promising approaches to compensate for imminent depletion of fossil energy resources and their adverse global impacts is enhancing the efficiency of systems utilizing low-temperature heat sources. The initial target of the research is to present a promising system for simultaneous production of power, refrigeration, heat, and hydrogen utilizing a combination of the absorption power cycle, the vapor compression refrigeration cycle, and a proton exchange membrane electrolyzer. On this subject, a comprehensive modeling of the energy and exergy of the proposed set-up is presented, and its thermodynamic performance is scrutinized. Furthermore, a comprehensive study of various parameters is performed to evaluate their impacts on system performance. The research aims to enhance and optimize the use of energy and various resources, contributing to the development of more sustainable efficient energy systems. Thermodynamic analysis of the multiple generation system shows that under baseline conditions and initial design, the system has the capability to produce net electrical power of approximately 17.12 kW, cooling power of about 201.5 kW, heating power of around 697.1 kW, and produce pure hydrogen at a rate of 0.153 kilograms per hour. The system exhibits an energy efficiency ratio of 1.364 and an exergy efficiency of 36.58 %. Moreover, optimization with single and multiple objectives with different weighting coefficients reveals that higher values of these parameters can be obtained. In other words, in the MOOM optimization mode, exergy efficiency increases to 7.16 %, and the energy performance ratio rises to 85.73 % compared to the BM mode. Additionally, through a parametric assessment to define the effect of input parameters on system performance, it demonstrates that increasing the temperature of the heat source may simultaneously increase the exergy efficiency and energy performance ratio of the system. The Grassmann diagram also indicates that the total exergy of the input fuel is about 196.9 kW. From this amount, approximately 121.5 kW are destroyed through the components of the system. Furthermore, about 3.39 kW are lost through the absorber coolant and waste from the hydrogen production unit. About 72.4 kW are attributed to products.

Low-Temperature Thermal Treatment and Boron Speciation Analysis from Coals

Despite urgent calls for decarbonization, the continued increasing demand for electricity, primarily from coals, has presented challenges in managing coal-derived wastes such as coal fly ash (CFA), which are enriched with environmentally hazardous substances like boron. This study explores a low-temperature heating process to remove boron from coal, aimed at preventing its condensation and enrichment into CFA during combustion. Initial boron concentrations in coals varied widely from 50 to 500 ppm by weight and were found to correlate with fixed carbon content (FC) through the following polynomial equation: [B]o = 0.0929(FC)2 − 14.388(FC) + 601.85; R2 = 0.9173. This relationship suggests that as coal undergoes coalification, boron-containing compounds are decomposed and released, resulting in a decline in boron levels as the coal matures. Boron-removal efficiency was investigated by drying coal samples at 110 °C, 160 °C, and 210 °C under natural air convection, and nuclear magnetic resonance (NMR) spectroscopy was used to assess changes in boron speciation during heating. Our results demonstrate that boron removal ranged from 5% to 82%, with minimal improvements observed beyond 110 °C. In addition, the 11B MAS-NMR spectra of the coal samples showed four peaks at isotropic chemical shift values of −1.0, 2.0, 8.0, and 14.0 ppm and suggested that the species of boron volatilized at low temperatures is the inorganic BO4 assigned to peak no. 0 at −1.0 ppm. The association of boron with inorganic components in coal suggests potential for efficient removal, particularly in coals with higher fixed carbon content. These findings highlight the viability of low-temperature thermal treatment as a cost-effective method for boron removal, which is crucial in mitigating the risks associated with coal combustion by-products.

Performance optimization and evaluation of integrating thermochemical energy storage with low-temperature driven absorption heat pump for building heating: 4E analyses

A heating system achieved by combining thermochemical energy storage and absorption heat pump is proposed and verified. Based on the experimental data, a mathematical model of the zeolite/water reactor is established and verified. By setting up a micro-compressor between the evaporator and absorber, the AHP is driven by low temperature source. Based on typical days in winter, the stable operation of the system is explored, and the influence of main parameters on the charging/discharging and heating processes are analyzed. The results show that the charging and heating efficiency reached 55.11% and 73.52% during the daytime. The discharging efficiency at night reaches 88.27%. The AHP can be driven by a heat source at a minimum of 75 °C, and hot water at 48.3 °C is provided. Parameters influence analysis shows that temperature is an important factor affecting the charging process, and the initial air temperature is recommended to increase. Humidity is the biggest influencing factor in the discharging process and easily changed and controlled. By replacing electric heating, the system can allow the investment to be recovered within 6.23 years. Environmental analysis shows that the proposed system has significant benefits in terms of primary energy savings and pollutant emission reduction

Performance prediction and regression analysis of scroll expander based on response surface methodology

The Organic Rankine Cycle (ORC) plays a pivotal role in the domain of renewable energy, adeptly harnessing thermal energy from sources such as solar and geothermal to generate electrical power. Central to this system is the scroll expander, whose operational efficacy directly influences the ORC's overall efficiency. This study initiates with a detailed numerical analysis of the impact of various operational parameters on both the steady and transient output performance of the scroll expander. Following this, a sophisticated performance prediction model is developed employing the response surface methodology. The model boasts high coefficients of determination, R2,values of 0.9967 and 0.9916, respectively, underscoring its superior predictive accuracy. Further, this model delves into the complex interactions among operational parameters and their consequent effects on the expander's performance. Validation of this predictive model is achieved through rigorous testing on an experimental platform designed for the ORC low-temperature waste heat power generation system. The discrepancies between predicted and actual performance measurements fall within a commendable margin of 15 %, affirming the model's robustness in forecasting scroll expander performance. The culmination of this research furnishes a novel and efficacious optimization strategy, establishing a robust theoretical foundation and offering fresh insights for the enhancement and prediction of scroll expander performance. This not only underscores the innovation of the approach but also its practical applicability in advancing the efficiency of renewable energy systems.

Sensitivity analysis on heat pump - mechanical vapor recompression desalination system by recovering waste heat of offshore power converter station

Abstract Offshore wind power converter stations produce massive low-temperature waste heat, which can hardly be used constrained by their offshore location. Therefore, the recovery of the waste heat has been raising widespread concern. Meanwhile, a large amount of fresh water is needed for its cooling system. So, a novel system combining high temperature heat pump and a mechanical vapor recompression system (HP-MVR) was proposed, and sensitivity analysis was performed to optimize it. The heat pump was used to absorb the waste heat and to produce high temperature water. The mechanical vapor recompression system was adopted to produce fresh water and to recover the condensation heat from the steam. In order to determine the impact parameters on the two crucial performance indicators of freshwater production and unit energy consumption, this article introduces a sensitivity analysis method, focusing on analyzing the sensitivity of the three operating parameters of heat pump condensation temperature, saturated water vapor inlet temperature entering the compressor, and freshwater condensation temperature to these two performance indicators. The results show that the sensitivity coefficients of heat pump condensation temperature, saturated water vapor inlet temperature entering the compressor, and freshwater condensation temperature are 1.13, -0.26, and 1.56. So, the freshwater condensation temperature has the most significant effect on freshwater output. Their sensitivity coefficients to unit energy consumption are 1.02, 1.41, and -0.64. The saturated water vapor inlet temperature entering the compressor has the most significant impact on the required power consumption per unit of freshwater. It will give some guidance for the application of low-temperature waste heat in seawater desalination and the reduction of operating costs.

Exceptional strength-ductility synergy in additively manufactured (CoCrNi)90Al5Ti5 medium-entropy alloy by heat treatment

Powder Plasma Arc Additive Manufacturing (PPA-AM) technique has tremendous potential for the practical application in medium-entropy alloys (MEAs). In this study, we investigated the effect of heat treatment on microstructural evolution, mechanical properties, and the work hardening behavior in the PPA-AM processed (CoCrNi)90Al5Ti5 MEA. The results show that the As-built specimen is a single-phase FCC structure, displaying <001> strong FCC texture in the deposition direction. The stacking faults (SFs) and dislocations were observed in the alloy, which formed the stacking fault networks and the Lomer-Cottrell locks structure. The plasticity of the alloy increased significantly after the high-temperature heat treatment, which can be attributed to the modifications of the microstructure, such as the weakening of the texture strength and the reduction of the stresses. Low-temperature heat treatment decreases the density of dislocations in the alloy, but promotes the generation of the co-lattice phase. The evolution of the dislocation density, texture strength, and precipitates significantly influenced the strain hardening behavior and mechanical properties. The tensile results showed that the strength and plasticity of the samples were increased after two-step heat treatment. The yield strength, ultimate tensile strength, and elongation to failure were 733 MPa, 1080 MPa, and 22.3%, respectively, which were 16.2%, 20.3%, and 15.5% higher than the As-built samples. This work elucidates the underlying mechanisms of heat treatment on the microstructure and mechanical properties of the alloy.

Copper‐Catalyzed One‐Pot Synthesis of 1,3,4‐Oxadiazol‐2(3H)‐ones using DMF as the Carbonyl Source

AbstractA series of 1,3,4‐oxadiazol‐2(3H)‐ones were prepared by an efficient copper‐catalyzed one‐pot reaction of arylhydrazides, arylboronic acids and DMF. Moderate to good yield of 1,3,4‐oxadiazol‐2(3H)‐ones were obtained using DMF as the carbonyl source and arylboronic as the aryl source. This reaction involved ligand exchange and transmetalation of copper catalysts with arylhydrazides and arylboric acids. Compared to the previous work, this work employs the stable and readily available aryl hydrazide and arylboronic substrates that enhance the practicality of this strategy, and this strategy features a short reaction time, relatively low heating temperature, convenient and more secure. Further, this protocol has the features of high functional group tolerance and reaction scalability.

Performance Evaluation of Heat Pump Systems Utilizing Construction Waste as a Low-Temperature Heat Source

Performance Evaluation of Heat Pump Systems Utilizing Construction Waste as a Low-Temperature Heat Source

Assessment of the impact of setting the heating curve on reducing gas consumption in a residential building while ensuring thermal comfort

Due to the large share of the residential building sector in CO2 emissions, it is necessary to look for quick-to-implement and cost-free solutions for heating systems aimed at increasing their efficiency and reducing fuel consumption. The aim of the study is a multi-aspect assessment of the proper setting of the heating curve in the weather controller of a low-temperature floor heating system with a condensing gas boiler, and an analysis of the impact of the heating curve slope on the natural gas consumption, the emission of gaseous and dust pollutants and on maintaining appropriate indoor air parameters: air temperature, operative temperature and PMV and PPD. A wide range of simulation tests were carried out using the TRNSYS software for an existing energy-efficient single-family residential building, with mechanical ventilation with heat recovery, located in north-eastern Poland in Bialystok. Changing the heating curve slope by 0.1 can reduce gas consumption and pollutant emissions by 1.6–10.3 %. Low heating curve slopes may result in failure to reach the temperature set by users (difference between the set and achieved indoor temperature up to 1.9 K), while maintaining standard thermal comfort parameters (−0.5<PMV<+0.5; PPD<10 %). Reducing the indoor air temperature by 2 K can contribute to reducing gas consumption by 11 % while maintaining standard thermal comfort parameters. Changing the heating curve slope is one of the effective methods of reducing fuel consumption in the building. Results are useful for users of buildings equipped with low-temperature heating systems with floor heating and installers of these systems.

Thermodynamic analysis of a hybrid ammonia-water refrigeration cycle with low-temperature solar heat

The performance of a solar-driven single-effect ammonia absorption refrigeration unit was studied numerically and experimentally. The thermal performance and unit operation status of small refrigerators were studied under various designing and operating conditions. A thermodynamic cycle scheme of hybrid ammonia-water refrigeration (HAWR) is proposed to operate in parallel with the compressor and ammonia absorption refrigeration, and the performance of the thermodynamic circulation system is evaluated by considering the thermodynamic coefficient and thermodynamic refrigeration ratio as evaluation indexes. Aspen Plus simulation software was introduced to simulate the HAWR and optimise the operation strategy. The results indicate that adjusting the compressor outlet pressure can stabilise the refrigeration capacity of the ammonia refrigeration system. The optimised working point pressure is 600 kPa, while the corresponding evaporation, condensation, absorption, and generation temperatures are 15 °C, 40 °C, 42 °C, and 85 °C respectively, the thermodynamic coefficient is 0.307, and the thermodynamic refrigeration ratio is 0.443. Under the rated cooling conditions, 44.3 % of the cooling capacity is driven by solar energy, and 55.7 % is driven by electric energy in the optimal working state. Under non-optimal working conditions, the proportion of the cooling capacity driven by electric energy is as high as 79.5 %. Under the conditions of sunny weather and with the absence of the compressor, the cooling capacity increases from 2.5 to 7.5 kW as the radiation intensity increases from 600 to 950 W/m2, while the system performance tends to be stable and the coefficient of performance maintains around 0.738 as the irradiation intensity exceeds 800 W/m2.

Low-grade heat to electricity conversion using the self-circulation of a magnet inside a single-turn pulsating heat pipe

Low-temperature (≤100°C) heat sources are abundantly and ubiquitously available in nature, such as solar energy, and in the form of untapped waste heat. This work aims to harness low-grade heat sources by introducing a portable harvesting system capable of effectively converting small spatial temperature gradients to mechanical and then electrical energy while maintaining a relatively high heat transfer capability. The designed and studied pair of harvesters are based on single-turn pulsating heat pipes with different condenser locations. Asymmetrical heating and cooling of the looped capillary glass tube gives rise to the bulk circulation of the internal fluid with occasional oscillation. The thermally-driven two-phase flow carries a spherical neodymium magnet fitted inside the tube. Two external solenoids generate a small amount of electricity every time the magnet passes through them. The proper functioning of energy-harvesting pulsating heat pipes (EH-PHPs) was investigated for pure water, acetone, and ethanol as the working fluids. Only water demonstrated satisfactory results and was thus selected as the main working fluid. Subsequently, high-frame-rate imaging of the internal flow along with time-domain temperature and open-circuit voltage data were employed and discussed to study the working principles of the harvester. In the next step, the mechanical, thermal, and electrical performance of the two EH-PHPs were quantitatively investigated for five different filling ratios (FRs) between 20% to 80% and five levels of heat input from 20.0W to 40.0W for each FR. Among the studied conditions, the EH-PHP with horizontal condenser (HC) configuration and 50% FR demonstrated the best performance in all three aspects. Accordingly, when 40.0W of heat was supplied to this ideal case, the magnet mean circulation frequency around the loop, effective thermal conductivity, and average induced open-circuit voltage (peak-to-peak) reached their maximum values of 0.46Hz, 11.5kW/(mK), and 0.53V, respectively. Although the integration of electromagnetic generators had reduced the heat transfer performance, the thermal conductivity of the EH-PHPs was comparable to that of conventional heat pipes and at least 25 times better than copper. Finally, the EH-PHP with HC configuration and 50% FR, the superior case, produced up to 5μW of electrical power while its solenoids were connected to load resistances with an optimum impedance. Therefore, even in its early stage of development, the portable EH-PHP can be used to supply low-power electronics such as a quartz watch. The generated electricity corresponds to about 0.01% relative Carnot efficiency. The remarkable thermal conductivity and capability of electricity production with less than 5°C temperature difference across the tube distinguish the EH-PHPs from mature energy harvesting technologies with higher energy conversion efficiencies.

Heat capacities and role of defects in ion transfer of quinuclidinium hexafluorophosphate plastic crystal

To study the phase behavior and role of defects in the ion conduction of a well-investigated plastic crystal electrolyte, we measured the low-temperature heat capacities of quinuclidinium hexafluorophosphate ([HQ]PF6) plastic crystal and the defects of pure [HQ]PF6 and its mixtures containing lithium ions and chloride ions. The heat capacities of the pure material show two solid‒solid phase transitions at room temperature and a low temperature. Positron annihilation lifetime spectroscopy (PALS) revealed the phase dependence of the defect size for both the pure material and the mixtures. The defects in these two mixtures expand largely to approximately 2 (with Li+) and 2.5 (with Cl−) times larger than those in the pure material. The relationships between the ionic conductivity and vacancy volume of the pure material and the mixtures obey the Cohen−Turnbull free volume model, which is also phase dependent. This work help elucidate defect-assisted ion transfer in organic ionic plastic crystals.

Design and analysis on the HP-PHRS for small modular lead-bismuth fast reactor

The heat pipe is an efficient heat-conducting element that can efficiently and passively transfer heat from a high-temperature heat source to a low-temperature heat source. It is widely used in the various industries. Based on high-temperature heat pipe technology, this paper designs a passive decay heat removal system for a small modular lead–bismuth fast reactor, and uses the system code ATHLET coupled with the heat pipe calculation module to calculate and analyze the thermal–hydraulic characteristics of the reactor under station black out accident.

Directional synthesis and application of long-chain ethers from biomass-derived carbonyls

The work introduced an innovative pathway for converting biomass-derived carbonyls into long-chain ethers, examining their low-temperature oxidation in a modified Cooperative Fuel Research (CFR) engine. The conversion of 2-butanone achieved 100 % and the selectivity of sec-butyl isopropyl ether reached the maximum of 83.13 % under optimal reaction conditions. Conversion of biomass-derived carbonyls increased from 31.77 % at 1 h to 36.28 % at 12 h, with the mass yield of long-chain ethers rising from 53.94 % to 62.86 %. At the same compression ratio, the maximum in-cylinder pressure and temperature increased as the long-chain ethers blending ratio increased. At the critical compression ratio, the net heat release rates (NHR) for blended fuels with 10 vol%, 20 vol% and 30 vol% long-chain ethers at the low-temperature heat release peak were 9.6 J/deg, 10.1 J/deg, and 10.0 J/deg better than that of n-heptane (6.3 J/deg), respectively. CO emissions from blended fuels before compression ignition were higher than n-heptane, while the value for the blended fuel with 30 vol.% long-chain ethers was reduced by 44.97 % compared to n-heptane after autoignition.

Effects of Low-Temperature Heat Treatment on Mechanical and Thermophysical Properties of Cu-10Sn Alloys Fabricated by Laser Powder Bed Fusion.

This study investigated the impact of low-temperature heat treatments on the mechanical and thermophysical properties of Cu-10Sn alloys fabricated by a laser powder bed fusion (LPBF) additive manufacturing (AM) process. The microstructure, phase structure, and mechanical and thermal properties of the LPBF Cu-10Sn samples were comparatively investigated under both the as-fabricated (AF) condition and after low-temperature heat treatments at 140, 180, 220, 260, and 300 °C. The results showed that the low-temperature heat treatments did not significantly affect the phase and grain structures of the Cu-10Sn alloys. Both pre- and post-treatment samples displayed consistent grain sizes, with no obvious X-ray diffraction angle shift for the α phase, indicating that atom diffusion of the Sn element is beyond the detection resolution of X-ray diffractometers (XRD). However, the 180 °C heat-treated sample exhibited the highest hardness, while the AF samples had the lowest hardness, which was most likely due to the generation of precipitates according to thermodynamics modeling. Heat-treated samples also displayed higher thermal diffusivity values than their AF counterpart. The AF sample had the longest lifetime of ~0.19 nanoseconds (ns) in the positron annihilation lifetime spectroscopy (PALS) test, indicating the presence of the most atomic-level defects.

Fabrication of binder-free TiO2 P 25 films on flexible PET/ITO substrate for photoanode in dye-sensitized solar cells

In this work, TiO2 P 25 films for photoanode in dye-sensitized solar cells (DSSCs) have been fabricated using a flexible PET/ITO substrate with a low-temperature heating technique. Ammonium hydroxide/ethanol solution was used as an alternative binding agent to fabricate TiO2 paste, which can be removed at low-temperature heating. The conventional screen print method is still used in DSSC fabrication because it is a very cheap and easy technique. A hot-pressing method is also used to improve the quality of TiO2 films and the performance of DSSCs. The encapsulation technique used in the assembly of DSSC is expected to increase the stability of DSSC devices to prevent electrolyte leakage. The resulting TiO2 film shows the highest DSSC performance using the hot-pressing and encapsulation method with PCE 0.29%. The encapsulation technique increased the stability of DSSC devices with more extended durability than without encapsulation.

Field, frequency, and temperature dependencies of the surface resistance of nitrogen diffused niobium superconducting radio frequency cavities

We investigate the rf performance of several single-cell superconducting radio-frequency cavities subjected to low temperature heat treatment in nitrogen environment. The cavities were treated at temperature 120–165 °C for an extended period of time (24–48 h) either in high vacuum or in a low partial pressure of ultrapure nitrogen. The improvement in Q0 with a Q rise was observed when nitrogen gas was injected at ∼300 °C during the cavity cooldown from 800 °C and held at 165 °C, without any degradation in accelerating gradient over the baseline performance. The treatment was applied to several elliptical cavities with frequency ranging from 0.75 to 3.0 GHz, showing an improved quality factor as a result of low temperature nitrogen treatments. The Q rise feature is similar to that achieved by nitrogen alloying Nb cavities at higher temperature, followed by material removal by electropolishing. The surface modification was confirmed by the change in electronic mean free path and tuned with the temperature and duration of heat treatment. The decrease of the temperature-dependent surface resistance with increasing rf field, resulting in a Q rise, becomes stronger with increasing frequency and decreasing temperature. The data suggest a crossover frequency of ∼0.95 GHz above that the Q rise phenomenon occurs at 2 K. Some of these results can be explained qualitatively with an existing model of intrinsic field-dependence of the surface resistance with both equilibrium and nonequilibrium quasiparticle distribution functions. The change in the Q slope below 0.95 GHz may result from masking contribution of trapped magnetic flux to the residual surface resistance. Published by the American Physical Society 2024

Effects of normalizing process on microstructure, texture, and precipitates of Sn bearing oriented silicon steel

Low temperature heating process of the slab has become the mainstream process for producing high quality oriented silicon steel due to its environmental protection, low cost, and high yield. For this process, the number of inhibitors is less and the size is large, resulting in insufficient inhibition, coarsen grains during primary recrystallization, and insufficient driving force for secondary recrystallization, which reduces the magnetic properties of the product. These shortcomings can be improved by optimizing the inhibitors and normalizing processes. The effects of normalizing processes on the microstructure, texture, and precipitations of low-temperature oriented silicon steel containing Sn were studied by OM, SEM, TEM, and EBSD with Fe–3%Si hot-rolled plate as initial material. The experimental results show that the sample has the best performance in terms of microstructure, texture, and precipitations with the two-stage boiling water cooling normalizing process that the heating temperature is 1150 °C, and the normalizing intermediate temperature is 850 °C. With the above parameters, the microstructure is inhomogeneous along thickness. There are more {111}<112> textures, which are favorable to the growth of Goss texture. The proportion of high energy grain boundary reached 54.2%. The precipitates are significantly refined, which enhances the ability to inhibit primary recrystallization. The sub-surface thickness of the hot rolled plate increases from 40.6% to 62.1% with increasing Sn content from 0.01% to 0.11%. The degree of tin segregation at grain boundary increases with the increase of normalizing temperature and the decrease of medium soaking temperature.