What Are Our Concerns About Bearings（56）

Q1:GB/T15826.1-9-95 which grade of forgings?

A:GB/T 15826.1-1995 is not forgings grade, but the national standard: hammer steel free forgings machining allowance and tolerance general requirements;  And this standard has been abolished, replaced by GB/T 21469-2008.  

Q2:Are there acceptance standards for pressure vessels and SG forgings?

A:Pressure vessel forgings acceptance standard:  

• NB/T47008-2010 (instead of JB4726-2000) forgings of carbon steel and low alloy steel for pressure vessels
• NB/T47009-2010 (instead of JB4727-2000) low alloy steel forgings for low temperature pressure vessels  
• NB/T47010-2010 (instead of JB4728-2000) forgings of stainless steel for pressure vessels  

Q3:How to determine the size of forging blank before hammering?

A:Small forgings blank size can be determined according to the national standard GB15826, Large forgings blank size can be determined according to the ministry of Machinery standard JB9179 

Q4:A234 is butt welded pipe fitting. Why does the standard include forgings?

A:ASTM A234 is the American standard for wrought carbon and alloy steel pipe fittings for medium and high temperatures.  Seamless or welded fittings may be available, and forgings are also permitted.  Only cast pipe fittings are not included in this standard.  The raw materials of pipe fittings in this standard may be plates, forgings, round steels and pipes, etc.  

Q5:What technical conditions are forgings sampled according to (especially size)?

A：There are many sampling standards, depending on what forgings, what to do, such as nuclear power forgings, Marine forgings, forgings for pressure vessels, etc., their sampling standards are different, the number and size of sampling, location and so on have different requirements.  

Q6:What is the acceptance standard for 1Cr13MoS forgings?

A:API610 standard or GB/T1220-2007.

Q7:What are the standard forgings of the valve? Which castings?

A:According to the working condition of the product, such as floating ball valve, under normal circumstances are cast to produce blank, but when the customer needs anti-corrosion requirements, we will use forgings to manufacture blank.  

Q8:What is NB/T47008A flaw detection standard?

A:NB/T 47008-2010 Carbon and alloy steel forgings for pressure bearing equipment. This standard specifies the technical requirements, test methods and inspection rules of carbon steel and alloy steel forgings for pressure bearing equipment.  This standard applies to carbon steel and alloy steel forgings for pressure bearing equipment whose design temperature is not less than -20℃ and design pressure is less than 100MPa.  

Q9:In industry, there are standard parts, castings, forgings, purchased parts, what are the meaning of all the above?  

A:Standard parts refer to the structure, size, drawing, marking and other aspects have been completely standardized, and the common zero (part) parts produced by professional factories, such as thread parts, keys, pins, rolling bearings and so on.  

Casting is a metal molding object obtained by a variety of casting methods, that is, the smelted liquid metal, with pouring, injection, inhalation or other casting methods into the pre-prepared casting, after cooling by falling sand, cleaning and post-processing, obtained with a certain shape, size and performance of the object.  

Forgings are objects in which metal is subjected to pressure and plastic deformation to form the desired shape or the appropriate compression force.  

Purchased parts generally refer to parts without standardization, which need to be designed and customized separately, that is, purchased from the outside, so called purchased parts.  

Q10:Is there any difference between ASTM A564 and ASTM A705?  Which standard does 630 use?  

A:ASTM A564 is the standard for aging hardened stainless steel bars and profiles for hot rolling and cold finishing rolling.

And ASTM A705 is the standard for age hardened stainless steel forgings.  

Their difference: one is hot rolled material, one is forging.  Which standard to use depends on whether you need hot rolled material or forging material.

630 is just one of the code names for the type of materia

Q11:Are forged flanges the same as forged flanges?  For THE PED certification of DNV, the standard of flange is American standard 16.5. What is the standard of forging?  

A:Forgings are relatively material in American standard. For example, ordinary carbon steel is A53 in steel pipe standard, A234 WPB in pipe fittings, and A105 in flange.  The same is true for alloy P5, F5 and Cr.5

Q12:What is the difference between 16Mn and 16MnD in steel?

• A:[1] 16Mn: low alloy steel forgings for pressure vessels that meet the impact of 0℃. 6MnD: D stands for low temperature. It is steel forgings for low temperature vessels that meet the impact of 40℃.  
• [2] Steel: Steel is widely used and of various varieties. According to the different section shapes, steel is generally divided into four categories: profile, plate, pipe and metal products.  Steel is steel ingot, billet or steel made by pressure processing of a certain shape, size and properties of the material.  Most steel processing is through pressure processing, so that the processed steel (billet, ingot, etc.) produce plastic deformation.  According to different steel processing temperature, can be divided into cold processing and hot processing two.  

Q13:Why must giant forgings be made by free forging?

A:Forging is not a casting.  

Forging with a special die is called die forging, forging without a special die is called free forging.  

Giant forgings are generally small in batch, and the cost of making giant molds is too high.  

In addition, forging with molds requires too big a press, and even if there are giant molds, there is no press that big.  At present, the largest domestic hydraulic press tonnage seems to be only 50 thousand tons.  The main reason is that the largest forging hammer in China is only 16 tons, and the equipment standard for large forgings is too low.  

General large die forgings in China mainly rely on imports, mias in Russia has a too 50 tons of air hammer, can forge 5 meters long Marine crankshaft, but because of his equipment is relatively old, forging accuracy is not high!  

There is also a method of splint hammer forging, which can be more accurate, so the general large forgings use free forging.  

Q14:What does 16MN need to do for 370 degree high temperature tensile test forgings?

A:Forgings for high temperature tensile test, to follow the national standard: GB/T 4338-2006 metal materials high temperature tensile test method.  This standard specifies the terms and definitions, symbols and names, test principles, test equipment, test specimens, test methods, results treatment and test reports of tensile test methods for metallic materials at temperatures higher than 35 degrees Celsius.  

Q15:Is UNS N06030 forged?

A:The UNS N06030 standards are as follows:  Forging or rolling OF UNS N06030, N06022, N06035, N06200, N06059, N06686, UNS NO8020, UNS NO8024, UNS NO8026, UNS FOR High temperature Corrosion Operations  NO8367, N10276, N10665, N10675, N10629, N08031, N06045, N06025 and R20033 alloy pipe flanges, forged fittings, valves and spare parts. It can be forged, of course, or rolled.