Steelmaking

Selecting secondary refining technology properly and pushing forward construction of high efficient and low cost“clean steel platform”

2010, 26(2): 1-9. doi:

Asbtract ( 661 )

Related Articles | Metrics

The iron and steel industry at home and abroad is now facing a very serious challenge of the worldwide financial crisis today. One of the key points for readjustment and rejuvenation of the iron and steel industry of China is to adjust and optimize the products and processes by means of scientific and technological progress and in the meanwhile acceleratedly pushing forward the construction of the high efficient and low cost “clean steel platform” has become one of the current scientific and technological innovative tasks of the iron and steel works. The development of secondary refining technology in China has already gone through three important phases, namely initial step, popularization and optimization and uptodate with a very clearcut guiding principle it has grown up to a certain level and scale and has accumulated experience and taken hold of quite a number of key technologies. However certain problems such as low refining ratio,incompetency of properly selection and application of the refining functions still need to be further improved.The high efficent and optimal technological processes of the secondary refining for such a few typical steel grades as the long products, hot rolled coils, medium plate and cold rolled sheets have to be studied and summarized in order to provide some referential experience for enterprises of the various kind. Deepening our understanding of the functions of different types of the secondary refining and properly selecting them will be propitous to the standardization of the basic secondary refining processes for different types of products as well as be beneficial to expedite the construction of the high efficient and low cost “clean steel platform”.

Production practice of smelting weather-resistant steel by increasing the intensity of oxygen supply

2010, 26(2): 10-12，5. doi:

Asbtract ( 1424 )

Related Articles | Metrics

Proceeding from the refining technologies of the weather resistant steel the present paper analyzes the effects of the intensity of oxygen supply on the smelting cycle, end point phosphor content and oxygen consumption. Practical results show that by increasing 5% oxygen flow the smelting cycle per heat can be reduced by 1.53min and the change of the end point phosphor content is of insignificance and the oxygen consumption per heat reduced by 9394m3. Thus the production cost is lowered and productivity raised obviously.

Application and development of technologies of slag amount control from converter to ladle in Shougang Group

2010, 26(2): 13-15. doi:

Asbtract ( 679 )

Related Articles | Metrics

Technological for slag amount control from converter to ladle have been improved to some extent by revamp of the equipments and innovation of technologies in Hebei Shougang Qian’an Iron & Steel Co., Ltd. For those low carbon steel grades used in automobile sheets up to date the thickness of the slag layer in the ladle can be controlled within an average of 33.7mm and the slag amount to ladle from converter be controlled in a mean value of 4.8kg/t. Besides, a rise of T.Fe content in the end point converter slag and absence of usage of slag detective and measurement devices may cause an increase of slag amount to the ladle.

RH process optimization in production of ULC steel by CSP process flow

2010, 26(2): 16-17，4. doi:

Asbtract ( 710 )

Related Articles | Metrics

The optimization of RH decarborization technology in production of extra-low carbon steel by the CSP process flow in Masteel has been expounded. By optimization of the RH-MFB oxygen blow process and control on the end point of BOF as well as an increase in the gas flow average end[C] of RH reaches 15ppm under the similar condition of RH treatment cycle. Thus Production of ULC steel in batch by CSP process flow can be ensured.

Research on technology of improving fluidity of molten steel

2010, 26(2): 18-21，6. doi:

Asbtract ( 1472 )

Related Articles | Metrics

Causes to the deterioration of flowability of the hot metal such as factors affecting the flowability in the process of raising the Ca-treatment effect, lowering the hot metal oxidation, optimizing the chemical compositions of the refractory materials, changing the mode of Al addition and intensifying control in the refining process have been studied on the basis of analysis on the clogging materials in the SEN. By adoption of appropriate technological counter measures the flowability of the hot metal has been effectively improved and the SEN clogging rate reduced as well.

Study & practice of nitrogen control technology of IF steel for ahtomobile use

2010, 26(2): 22-25，6. doi:

Asbtract ( 620 )

Related Articles | Metrics

By means of studies on the denitrification in combined blown converter,nitrogen pick-up in tapping, denitrification in RH treatment and nitrogen pick-up in CC in connection with the practice of refining the IF steel for automobile sheet purpose in the No3 Branch of the General Steel-making Plant a complete set of nitrogen control measures for overall process have been formed. As the results the Nitrogen content of IF steel is controlled effectively in 17.64×10-6,the average value, 20×10-6 and the best 10×10-6..

Exergy analysis of converter steelmaking process

2010, 26(2): 26-28. doi:

Asbtract ( 1525 )

Related Articles | Metrics

The energy conversion process in the converter steel-making is analyzed by building up a energy analysis model for the purpose of study on the converter steel-making process. Results show that the exergy loss per ton is 439.54MJ, in which external loss takes up about 96.63% of total loss, and the exergy loss induced by converter deslagging is about 69.29% of total exergy loss. Pivot points for reduction of the energy loss in the process of converter steel-making are controlling the converter slag amount and reclaiming and reusing the residual heat of the converter slag.

Analysis on thermal stress for stainless steel AOD converter of 120 t

2010, 26(2): 29-32. doi:

Asbtract ( 1542 )

Related Articles | Metrics

Thermal stress simulation analysis is carried out on the newly designed 120t stainless steel AOD converter. Firstly pretreatment is made on the CAE model with the main stream CAE software HYPERMESH universally adopted over the world and then analysis conducted on the temperature field and thermal stress simulation of the converter system in operation using the finite element analysis software ANSYS and finally post treatment made on the results of the simulation analysis with the software HYPERMESH once more. In this way the characteristic data of thermal stress for the 120t stainless steel AOD converter in operation is obtained and the result of the specific analysis is beneficial to implementation of the design and production maintenance.

Study on cleanliness of SPHC steel produced by optimized refining process

2010, 26(2): 33-36，5. doi:

Asbtract ( 637 )

Related Articles | Metrics

Cleanliness of SPHC steel produced by optimized refining process has been investigated and the total oxygen and nitrogen contents and the law of variation of the micro inclusions as well as the large inclusions in the cast slab and billet after RH and LF refining systematically studied by sampling and analyzing comprehensively。The results show that in the SPHC slab produced by the processing route of hot metal pretreatment(desulphurization)—120t top and bottom combined blown converter—RH (Ca treatment)—continuous casting the total oxygen content and nitrogen content is 23×10-6 and 17×10-6 respectively and the chemical compositions of the slab are completely in conformity to the requirements and the amount of large inclusions in 10kg slab is 4.76mg, which is basically in agreement with the cleanliness of the slab produced with the original process and higher cleanliness of SPHC slab can be achieved by further optimizing the RH refining process.

Study on deep desulphurization technology in refining to pipeline steel

2010, 26(2): 37-41. doi:

Asbtract ( 667 )

Related Articles | Metrics

By the laboratory research on the deep desulphurizer for pipeline steel, an optimal ingredient scheme, namely lime blended with aluminize powder is established. Through analysis of different process routes the final pipeline steel production route is determined in this plant. The industrialization verification experiment on the usage of the deep desulphurizer is carried out in connection with the final production route and then the flowing point of the congruent melting slag system is detected after using the deep desulphurizer so as to guarantee the good fluidity of the slag system at the normal desulphurization temperature. The aim of desulfurization smaller than 0.0010% and the desulfurization rate larger than 80% is achieved preliminarily.

process study on nitrogen pick-up in non-quenched and tempered crankshaft steel 48MnV-C

2010, 26(2): 42-44，7. doi:

Asbtract ( 698 )

Related Articles | Metrics

The non-quenched and tempered crankshaft steel 48MnV-C can be produced by adopting the process flow of “Converter→RH+LF→bloom continuous casting ”. The nitride manganese is added into the steel to increase the nitrogen content during LF refining. In this way the nitrogen content in the steel can be controlled consistently in the range of (108～134) ×10-6, the average value is 120 ×10-6, and the “white flake” in mill bar can be prevented.

Water modeling and industrial trial experiment on argon bubbling curtain in tundish

2010, 26(2): 45-48. doi:

Asbtract ( 750 )

Related Articles | Metrics

The influence of argon blowing at tundish bottom on flow field in tundish and removal of large-sized inclusions in slab was studied by water modeling and industrial trial. Water modeling results show that flow field could be improved obviously, volume fraction of dead zone decreased and residence time increased by argon bubbling. The flow characteristics could be improved variously under different experimental parameters. Industrial trial results show that argon bubbling curtain in tundish is an effective means to remove large-sized inclusion, especially for the inclusion with diameter less than 140μm. The decrease ratio of total oxygen content from long nozzle zone to slab is increased by 37.74%. With argon blowing, large-sized inclusions content of slab decreased from 3.85 mg to 2.88 mg per 10kg sample.

Influence of additive on melting temperature and Al2O3 inclusion absorption for thin slab continuous casting mould flux

2010, 26(2): 49-52. doi:

Asbtract ( 1448 )

Related Articles | Metrics

The effects of addition of different additive on the melting temperature change after asorption of Al2O3 by the mold flux and on the absorptivity of the mold flux additive for the Al2O3 have been studied. Experimental results show that the melting temperature tends to decrease as the addition of Li2CO3 increases from 4% to 10% and in addition of man-made cryolite and borax the melting temperature tends to rise when addition of Al2O3 increases to 6% from 3% and at the juncture of 6% Al2O3 the melting temperature shows a downtrend obviously. The order of influence of different additives on the absorptivity of mold flux for the Al2O3 lines up as Li2CO3＞NaF＞Na2CO3＞man-made cryolite＞borate. The experimental results are of certain significance in guiding the design of the thin slab CC mold flux.

Investigation in factors causing mold flux rim during slab continuous casting

2010, 26(2): 53-56. doi:

Asbtract ( 1461 )

Related Articles | Metrics

In light of the fact that mold flux rim usually appears during slab continuous casting of low alloy steel Q345D at Han-Steel the present paper studies the formation mechanism of flux rim, and confirms the factors causing the flux rim during casting by chemical analysis, laboratory scale melting and viscosity testing and scanning electron microscopy (SEM) et al. Results show that uneven melting and ill-fitted mixing of carbon materials are primary factors causing occurrence of the flux rim in the casting process and high crystallization temperature and deep molten flux layer tends to occurrence of the defect as well

Development and application of AOD equipments in refining stainless steel

2010, 26(2): 57-60. doi:

Asbtract ( 671 )

Related Articles | Metrics

Adoption of AOD equipments for refining stainless steel takes on a very important place in the stainless steel refining process. With the ever rising of the stainless steel output and technological level of refining in China it looks extremely important for the Country to develop the AOD equipments with self-determined intellectual property right. On the basis of accumulation of stainless steel smelting engineering technology for many years CERI has developed the equipments of AOD converter with independent intellectual property rights. This set of equipment is a truly home made equipment worthwhile popularizing broadly.

Revamp on sub-lance system of No.4 and 5 converters at No.2 Steel-makingPlant of Baosteel

2010, 26(2): 61-63. doi:

Asbtract ( 1544 )

Related Articles | Metrics

The present paper introduces the functions of sub-lance、its features and the disadvantages existing in operation in the No.2 Steel-making Plant of Baosteel and brings forwards the doable optimization projects. By means of equipment revamp and process optimization the problems existing in the original sub-lance systems are solved and the expected goal for the revamp achieved and the key technologies for the design and construction of the sub-lance system mastered, thus practical experience is accumulated for construction and revamp of the sub-lane system of the similar kind in the other Works.

Process optimization for increasing the RH snorkel life

2010, 26(2): 64-67. doi:

Asbtract ( 707 )

Related Articles | Metrics

The present paper analyzes causes leading to low RH snorkel life in our steelmaking plant. By optimization of the ring brickwork, improvement in welding quality of the dip tube, perfection of hot gunning process and optimization of steel refining process the average service life of the RH snorkel has been dramatically increased ( from 41.3 heats to 91.6, the tiptop to 122 heats).

Increase in dust removal ability of converter gas cleaning systemin production practice

2010, 26(2): 68-70. doi:

Asbtract ( 685 )

Related Articles | Metrics

By increase in the new equipments, revamp on the existing onesand adjustment of the parameters in the No.2 Steel-making Plant of Anshan Iron & Steel Co., Ltd, emission of the dust from the stack is obviously reduced and energy consumption of blower lowered and gas and steam reclamation raised in great scale and therefore the dust removal capability of the primary dust removal system of converter as well as the environment protection level are raised.

Experimental study of effect of steel slag on the activity of BF slag cement

2010, 26(2): 71-74. doi:

Asbtract ( 659 )

Related Articles | Metrics

In this paper, the effect of steel slag with different ratio on the activity of BF slag cement was researched. Study shows that for the steel slag blending with less than 20% composite powder its activity level index can meet the standard of S95 grade BF slag powder and the product quality will remain intact. If the quality fraction of the composite powder takes up 20 to 40% of the total cementations materials and 20% slag powder is blended with 80% BF slag powder the 7 day activity index will attain 75% and 28 day activity index 98%, and the results could be better than the use of the BF slag exclusively.

Comparison and analysis of steel slag treatment method and comprehensive utilization

2010, 26(2): 75-78. doi:

Asbtract ( 707 )

Related Articles | Metrics

The present paper introduces and compares the main processing methods of the steel slag disposal in China. Results show that the steel slag comprehensive utilization and residual heat reclamation are still in the phase of research and development and haven’t been applied into industrial production broadly and therefore development of a new type steel slag disposal process for appropriate use of the resource is impending.

Table of Content