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1. Allowable burr height of punching parts (1) limit value of burr of blanking parts It is not allowed that the burr of blanking parts exceeds a certain height. The limit value of burr height of stamping parts (mm) is shown in the table below.  (2) marking requirements for burrs in design drawings *Burr direction: burr side. *Parts requiring burring: coin or coin continue. Generally, do not press all the burrs on the fracture of the whole structural member, which will increase the cost. Try to use it in the following situations: the fracture exposed to the outside; Sharp edges…

Except that the symbol "SM" is added at the head, the representation method of plastic mold steel is the same as that of high-quality carbon structural steel and alloy tool steel. For example, the grade of carbon plastic die steel with an average carbon content of 0.45% is expressed as "sm45"; Alloy plastic die steel with average carbon content of 0.34%, chromium content of 1.70% and molybdenum content of 0.42% is indicated as "sm3cr2mo".

For non quenched and tempered mechanical structural steel, the symbols "YF" and "F" are respectively added at the head of the brand to represent free cutting non quenched and tempered mechanical structural steel and non quenched and tempered mechanical structural steel for hot forging. Other contents of the brand representation method are the same as those of alloy structural steel. For example: "yf35v", "f45v". Tool steel is divided into carbon tool steel, alloy tool steel and high-speed tool steel. ① Carbon tool steel is represented by standard chemical element symbols, symbols specified in Table 1 and Arabic numerals. Arabic numerals…

Free cutting steel is represented by standard chemical element symbols, symbols specified in Table 1 and Arabic numerals. Arabic numerals indicate the average carbon content (in tens of thousands). ① For sulfur free cutting steel and sulfur and phosphorus free cutting steel, the free cutting element symbol is not added after the symbol "Y" and Arabic numerals. For example, the grade of free cutting steel with an average carbon content of 0.15% is expressed as "Y15" ② For sulfur or sulfur and phosphorus free cutting steel with high manganese content, manganese element symbol shall be added after the symbol "Y"…

The grades of stainless steel and heat-resistant steel are indicated by alloy element symbols and Arabic numerals specified in the standard. For cutting stainless steel and free cutting heat-resistant steel, add "Y" at the head of the grade. Generally, one Arabic numeral is used to represent the average carbon content (in thousands); When the average carbon content is ≥ 1.00%, it is represented by two Arabic numerals; When the upper limit of carbon content is less than 0.10%, the carbon content is represented by "0"; When the upper limit of carbon content is ≤ 0.03% and > 0.01% (ultra-low carbon),…

① The grades of alloy structural steel are indicated by Arabic numerals and standard chemical element symbols. Use two Arabic numerals to represent the average carbon content (in tens of thousands) and put it at the head of the brand. The expression method of alloy element content is: when the average content is less than 1.50%, only elements are indicated in the brand, and generally the content is not indicated; When the average alloy content is 1.50% ～ 2.49%, 2.50% ～ 3.49%, 3.50% ～ 4.49%, 4.50% ～ 5.49%,... Write 2, 3, 4, 5... After the alloy element. For example, when…

High quality carbon structural steel adopts two Arabic numerals (the average carbon content is expressed in tens of thousands) or Arabic numerals and element symbols to form a brand. ① For, rimmed steel and semi killed steel, the symbols "F" and "B" shall be added at the end of the grade respectively. For example, the grade of rimmed steel with an average carbon content of 0.08% is expressed as "08F"; The grade of semi killed steel with an average carbon content of 0.10% is expressed as "10B". ② . killed steel (s and P ≤ 0.035% respectively) is generally not…

Carbon structural steel and low-alloy high-strength structural steel are usually divided into general steel and special steel. The brand representation method is composed of the Chinese phonetic alphabet of the yield point or yield strength of the steel, the value of the yield point or yield strength, the quality grade of the steel, and the deoxidation degree of the steel, which is actually composed of four parts. ① The Pinyin letter "Q" representing the yield point is used for general structural steel. The yield point value (unit: MPa), quality grade (a, B, C, D, e), deoxidation method (F, B, Z,…

The designation of steel products in China is generally expressed by the combination of Chinese Pinyin letters, chemical element symbols and Arabic numerals. Namely: ① Chemical elements in steel grades are represented by international chemical symbols, such as Si, Mn, Cr, etc. Mixed rare earth elements are represented by "re" (or "XT"). ② Product name, purpose, smelting and pouring method, etc. are generally represented by abbreviations of Chinese pinyin, ③ The content (%) of main chemical elements in steel is expressed in Arabic numerals. When the Chinese phonetic alphabet is used to represent the product name, purpose, characteristics and process…