December 1, Question 107 on Boiler Foundations: (A certain score will be given to the top 50)

Before the identification of new steel grade materials, they shall not be produced in batches, nor shall they be used for the trial production of boiler pressure components. (Incorrect) Article 26: Before using newly developed steel grades in the production of boiler pressure components, the steel manufacturer must conduct a technical evaluation of the testing of these new materials. The entities involved in this evaluation should include relevant departments and organizations such as those in the fields of metallurgy, manufacturing, operation, safety supervision, and standards. The evaluation should include at least the following: 1. Chemical composition. Experimental data to determine the upper and lower limits of the chemical composition should be provided. 2. Mechanical properties and tissue stability. The tensile strength σ and yield strength σ.2 shall be provided at temperature intervals of 20°C within the operating temperature range (up to 50°C above the maximum allowable operating temperature); in cases where this is not feasible, intervals of 50°C may be used. In addition, the elongation δ5, reduction of area, aging impact value, room-temperature Charpy (“V”-notched) impact energy, and brittle transition temperature shall also be provided. For carbon steel, low-carbon manganese steel, and low-carbon manganese vanadium steel with operating temperatures above 350°C, as well as other alloy steels with operating temperatures above 400°C, data on endurance strength, resistance to aging, and long-term aging stability shall be provided. For austenitic steels, intergranular corrosion resistance data should also be provided. 3·Antioxidant property. For boiler steels used at temperatures above 500°C, oxidation resistance data at the operating temperature (including 20°C above the maximum allowable operating temperature) shall be provided. 4. Heat fatigue resistance: The elastic modulus (E), average linear expansion coefficient (α), and heat transfer coefficient (λ) at the corresponding temperatures should be provided. 5·Welding properties. Data on the weldability of the steel and the mechanical properties of the welded joints should be provided. 6. Manufacturing processes of steel materials. Appropriate technical documents should be provided, such as those related to smelting, casting or rolling, and heat treatment of the finished products. 7·Thermal processing properties of steel. Corresponding technical data should be provided, such as information on hot stamping, hot rolling, heat treatment, etc. Article 27: Only after new steel grade materials have been approved through technical evaluation may boiler manufacturers proceed with the procedures for fabricating pressure components of boilers in accordance with Article 6 of these regulations. The boiler manufacturers participating in the trial production shall submit the performance reports, retesting reports, process test reports, and details of the trial production for the new steel grades to the safety supervision agency of the Ministry of Labor for record-keeping. Article 28: Before mass production of new steel grade materials, product evaluation must be conducted. Representatives from sectors such as metallurgy, manufacturing, use, safety supervision agencies, and standards should participate in this assessment. The manufacturer of the newly developed steel grades shall submit the evaluation results, trial usage outcomes, and the quality stability of the steel produced in bulk to the safety supervision agency of the Ministry of Labor for record-keeping.

This post was last edited by zhaozq2015 on 2015-12-1 08:13. New alloy materials shall not be produced in batches nor used for the trial manufacture of boiler pressure components prior to their identification. ( X )

Before the identification of new steel grade materials, they shall not be produced in batches, nor shall they be used for the trial production of boiler pressure components. (Correct)

Before the identification of new steel grade materials, they shall not be produced in batches, nor shall they be used for the trial production of boiler pressure components. (Yes)

Before the identification of new steel grade materials, they shall not be produced in batches, nor shall they be used for the trial production of boiler pressure components. (Correct)

Before the identification of new steel grade materials, they shall not be produced in batches, nor shall they be used for the trial production of boiler pressure components. (right)

Before the identification of new steel grade materials, they shall not be produced in batches, nor shall they be used for the trial production of boiler pressure components. (right)