At present time, the steel 20CrMo is produced according to GB/T3077—99 in our company. In order to produce high grade gear steel, sampling and test were made by according to GB/T5216, the processing quality of concasting billet supplied by Pangang Steel was investigated in detail, the main performance index of bar steel 20CrMo in our company was obtained.

Besides, it is important to ascertain the model parameter, but in practice the parameter always changes largely, which makes infection to the result, because of sampling and test instrument and test method and process and the sleight degree of workers and so on.

Various sampling methods for joint quality test of hot-rolled steel bar are introduced and discussed from flash butt welding, arc welding, electroslag welding and other aspects. According to different joints various sampling and test results evaluation methods are introduced in detail.

For obtaining the property and ingredient parameters of green sand contemporary and quickly, a multifunctional test system of evaluating green sand has been introduced, which consists of automatic sampling and test, pneumatic control loop, test and control part by MCU and PC.

The proper understanding and use of the chamber techniques, material sampling and test specimen preparation is crucial of obtaining reliable results.

Sampling and test methods for determining materials strength and other properties are similarly contained in Chapters 5 through 8.

A supplement to this document will be published later to address sampling and test methods relating to air contamination.

The number (ηt) of sample trees for physical and mechanical tests can be calculated by the-following equation: n_t=2~2 CV_t~2/εWhere CV_t: the estimated value of coefficient of variation of population with tree mean as the unit (percent); ε: allowed deviation (percent).One bolt is taken at the middle of height to lowest branch from each sample tree, which canbetter represent the mean value of properties of the trunk (Tab. 2.3). It seems that the traditional method for taking the bolt at the breat height...

The number (ηt) of sample trees for physical and mechanical tests can be calculated by the-following equation: n_t=2~2 CV_t~2/εWhere CV_t: the estimated value of coefficient of variation of population with tree mean as the unit (percent); ε: allowed deviation (percent).One bolt is taken at the middle of height to lowest branch from each sample tree, which canbetter represent the mean value of properties of the trunk (Tab. 2.3). It seems that the traditional method for taking the bolt at the breat height upwards, which makes the large log below the b. h. short and out of grade, should be changed. The test pieces can be taken at one radius from a large bolt because the difference of properties between opposite radius taken at random is generally not significant (Tab. 2.1). The variation of radial position at one level in the trunk is usually significant (Tab. 2.1). According to the analysis on nine samples of Chinese fir and Masson pine the variability of properties within the tree is significant and is greater than that between the trees(Tab.2·4).The optimum number of test pieces for each tree can be estimatedby the following equation: S(?)％=(S_T/(n_t)~(1/2)×100)/(?) (1+(S_s~2/u_sS_T~2))~(1/2)=S(?)T(1+r/n_s)~(1/2) where S(?): standard error of sample mean;S_T~2: component of variance between trees;S_s~2: variance within trees;n_t: number of Sample trees;n_s: number of test pieces per tree;r: S_s~2/S_T~2;S(?)T:(S_T/(n_t)~(1/2))/(?)t.The CV_s and CV_t, coefficients of variation with test piece as the unit and with tree mean as the unit respectively, approximately show a linear relationship (Tab. 3) with which the estimated value of CV_t is calculated from the value of approximate upper-limit of CV_s.According to the analysis of the existing data of a quantity of tests done the CV_t in equation (1) and the sample size can assume the estimated values as follows. The sampling method drawn has been principally proved on the level ε=15％and the results show that it can most likely satisfy the scheduled precision and realize economical efficiency.Some proposals for revision have been brought up on the sampling and testing method for a lot of timber of architectural engineering [GBJ5—73 (temporary standard)].

Impact value is one of the criteria to evaluate material toughness. The sampling and impact testing methods vary a lot; but the relationship between each sampling and testing method is mostly concerned. This paper discusses the relationship between the results obtained with all sampling and testing methods in ASTM E-23 in order to reveal the effects of different specimen and different testing method on the impact value.

In gas chromatograghy analysis of transformer oil, one usually meets some promblems in sampling and testing process, such as how to handle carrier gas, insert gasket, sample inserting and injector etc. These promblems can be solved by taking suitable measures accordingly and careful operations to perform the analysis. The accuracy and capability of diagnosis of potential transformer fault can be further improved thereby.