Use the fly, CS - 995 carbon sulfur analysis the carbon and sulfur content in iron and steel

Use the fly, CS – 995 carbon sulfur analysis the carbon and sulfur content in iron and steel

Introduction

Using CS – 995 high frequency infrared carbon sulfur instrument on the determination of samples with different carbon and sulfur content of steel are discussed, the tungsten grains flux only add method, the precision, accuracy and recovery, found that the determination results satisfied, according with the national standard, recovery in the 98.63-106.2%.

Carbon is an important element in steel alloy, is the difference between iron and steel, the important indexes of the steel grade, grade. The performance of the carbon steel alloy plays a decisive role. The measurement method of the lot, are usually put sample at high temperature combustion in oxygen flow, make it into carbon dioxide, then use the appropriate method determination of conventional measuring methods with gas volumetric method and conductance method, power method, non-aqueous titration, spectrophotometry, chromatography, etc. High carbon amount of conventional or these methods have their own advantages and disadvantages, generally can achieve the desired effect, but for the determination of ultra-low carbon also can not meet the requirements, and complicated operation, chemical reagent dosage, environmental pollution, the analysis of the cycle is long, not fit for the production control analysis.

Sulfur was identified inside the steel alloy of harmful elements, can cause the brittleness of steel, reduce the mechanical properties of steel alloy, especially a significant reduction in the fatigue limit, plasticity and abrasion resistance, affect the service life of steel alloy, at the same time, the sulfur for alloy steelThe corrosion resistance and weldability has bad influence. Method of determination of sulfur in iron alloy is more, such as barium sulfate weight method, the combustion – titration method (and neutralization by iodine volume method), conductance method, hydrogen sulfide method, infrared absorption method, etc. Barium sulfate weight method, while high testing precision, measurement of the lower limit is high, operation trival, analysis cycle is long, don’t adapt to the production control analysis; And burning – iodine law exists tube furnace heating speed slow, poor precision, the high content of samples, titration is hard to control, easy to cause such problems as the results of the analysis on the low side. Conductance method measuring curing method also exist complicated operation, analysis of the cycle is long, analysis and control are greatly influenced by individual condition factors, etc.

By using high frequency combustion infrared absorption method for determination of carbon and sulfur content in iron and steel samples, convenient and quick, high precision, accuracy, linear range, low detection limit, and is influenced by the individual elements.

Use the fly, CS – 995 carbon sulfur analysis the carbon and sulfur content in iron and steel

Experiment

11.1 instruments and reagents

CS – 995 infrared carbon sulfur analyzer

Porcelain crucible

The steel sample (national testing center of iron and steel material)

Tungsten flux

1.2 the instrument working conditions

High frequency furnace top oxygen flow rate: 1.4 litres per minute, analysis of gas flow rate: 3.2 litres per minute, carrier gas pressure: 0.08 MPa. The oxygen purity is not less than 99.5%; Oxygen blowing time: 20 seconds; Analysis of time: 45 seconds.

1.3 methods

According to samples from 0.3 g in ceramic crucible, add a spoonful of tungsten flux (1.5 g), to the instrument, began after measuring instrument is stable.

2 the results and discussion

2.1 the selection of flux

Flux is usually used in the determination of carbon and sulfur in steel with pure copper, copper oxide and tungsten grain, etc. This experiment adopts the tungsten grain of flux. Experiments show that the joining of tungsten particle flux steel samples, the samples of the melt flowing, release the complete combustion curve, measuring stability is very good. So in the experiments adopt the method of adding tungsten particle flux, effect is good.

2.2 according to the choice of sample weight

Determination of carbon and sulfur in steel sample, the sample of the said amount control in commonly 0.3 0.5 g. Found by experiments that the sample weight is 0.5 g, sample combustion enough, after the burning melt enough brightness, appear even the black block. When measuring high content of samples, dust is bigger. So generally choose 0.3 g as the best sample quantity

2.3 precision test instrument

Standard samples of different content ranges were used for repeated measurement 7 times under the same condition to investigate the stability of the instrument in different content range of standard samples. The data are shown in Table 1, Table 2, Table 3 and Table 4.

Use the fly, CS – 995 carbon sulfur analysis the carbon and sulfur content in iron and steel

Table 1 Precision inspection of low carbon and high sulfur standard samples

The precision of the standard sample of carbon and sulfur in Table 2 is investigated

Table 3 Precision inspection of high carbon and sulfur standard samples

Table 4 Precision experiment of low carbon and low sulfur standard samples

Use the fly, CS – 995 carbon sulfur analysis the carbon and sulfur content in iron and steel

From table 1 and table 2, table 3 and table 4 of the determination results, the relative error of the measured value and standard value in the range of allowable gb (RSD < 1%, carbon sulfur RSD < 4%), the instrument measuring the good stability and high precision.

2.4 accuracy test instrument

For different determination of carbon content in the prototype repeat 3 times, calculating the relative error, the data listed in table 5.

Use the fly, CS – 995 carbon sulfur analysis the carbon and sulfur content in iron and steel

2.5 standard addition recovery rate

At 11118-94, steel prototype YSBC GSB H40093 and GBS H 40118-96 as sample, respectively, to join the steel sample GBW (E), 010022, and YSBC YSBC28072-95 11140-2007, measuring its recovery rate, the results listed in table 7-11. Results show that the different carbon and sulfur content of 1 sample recovery rate is high, the method is suitable for the determination of carbon and sulfur content in iron and steel samples.

3 summary

Can be seen from the above analysis results, using the method of the CS – 995 carbon sulfur analyzer can accurately measuring steel samples of different carbon sulphur concentration, which conforms to the national standard in precision, repeatability and accuracy requirements. Can be thought of, this analysis method is a good way to test.