The technological properties of reinforcing bars include many items. Different requirements can be put forward according to the characteristics of different products, such as bending and reverse bending (reverse bending) tests for ordinary reinforcing bars, and repeated bending, torsion and winding tests for some prestressing steel bars.

　　所有這些試驗(yàn)的形式不同程度地模擬了材料在實(shí)際使用時(shí)可能涉及的工藝加工方式，如普通鋼筋需要彎鉤或彎曲成型，預(yù)應(yīng)力鋼絲有時(shí)需纏繞等，而其目的就是考核材料對(duì)這些特定塑性變形的極限承受能力，因而工藝性能也是對(duì)材料的塑性要求，且與上述延性（伸長(zhǎng)率）要求是相通的，一般來(lái)說(shuō)伸長(zhǎng)率大的鋼材，其工藝性能也好。

　　All of these tests simulate to varying degrees the processing methods that may be involved in the actual use of materials, such as bending or bending of ordinary steel bars, winding of prestressing steel wires, etc. The purpose of these tests is to assess the material's ultimate bearing capacity for these specific plastic deformation, so the process performance is also a plastic requirement of materials, and is in line with the ductility (extension) mentioned above. Length) Requirements are common. Generally speaking, steel with high elongation has good technological properties.

　　然而與拉伸時(shí)的單向受力狀態(tài)相比，工藝性能試驗(yàn)的受力狀態(tài)就復(fù)雜得多，試樣變形類型與大小則各向（軸向、徑向）不同，鋼材的組織結(jié)構(gòu)、晶粒大小、有害殘余元素含量特別是內(nèi)部和表面任何影響連續(xù)變形的缺陷如裂紋、夾雜等都可能影響和導(dǎo)致試驗(yàn)不通過(guò)。所以在某種意義上，對(duì)于考核鋼材的質(zhì)量，可以說(shuō)工藝性能試驗(yàn)更為嚴(yán)格。

　　However, compared with the unidirectional stress state under tension, the stress state of the process performance test is much more complex. The deformation type of the specimen is different from that of the specimen in all directions (axial and radial). The structure, grain size, harmful residual element content of the steel, especially any defect, such as cracks and inclusions, which affect the continuous deformation of the internal and surface, may affect and lead to the failure of the test. Therefore, in a sense, for the assessment of steel quality, it can be said that the process performance test is more stringent.

　　另外鋼筋的反向彎曲試驗(yàn)本質(zhì)上是一項(xiàng)應(yīng)變時(shí)效敏感性試驗(yàn)這是由于鋼水中一般都含有一定數(shù)量的游離氮（N），也稱殘余氮，含量過(guò)高時(shí)，可導(dǎo)致鋼材經(jīng)塑性變形后在室溫下脆化。

　　In addition, the reverse bending test of steel bar is essentially a strain aging sensitivity test, which is due to a certain amount of free nitrogen (N), also known as residual nitrogen, in molten steel. When the content is too high, the steel can be brittle at room temperature after plastic deformation.

　　由于鋼筋常常需彎曲成型以后使用，已經(jīng)產(chǎn)生了塑性變形，如果材性變脆，結(jié)構(gòu)就不能承受使鋼筋再產(chǎn)生塑性變形的外加荷載（如地震），所以目前國(guó)內(nèi)外都將反彎試驗(yàn)作為一項(xiàng)重要技術(shù)要求列入鋼筋標(biāo)準(zhǔn)，同時(shí)對(duì)鋼的氮含量予以限制（不超過(guò)0.012%）。

　　Because steel bars often need to be used after bending forming, plastic deformation has been produced. If the material is brittle, the structure can not bear the additional load (such as earthquake) which makes the steel bars plastic deformation again. At present, the bending test is included in the steel bar standard as an important technical requirement at home and abroad, and the nitrogen content of the steel is limited (no more than 0.012%).

　　研究表明，用于鋼的微合金化的一些元素如釩、鈦、鈮等，特別是釩與氮有極好的親和力，鋼中加入釩可有效結(jié)合自由氮，釩與氮的結(jié)合還能進(jìn)一步增強(qiáng)釩對(duì)鋼的強(qiáng)化效果，因此有些標(biāo)準(zhǔn)也注明“如果有足夠的與氮結(jié)合的元素存在氮含量可以高出標(biāo)準(zhǔn)規(guī)定”。

　　The results show that some elements used in steel microalloying, such as vanadium, titanium, niobium and so on, especially vanadium and nitrogen have excellent affinity. The addition of vanadium into steel can effectively combine free nitrogen, and the combination of vanadium and nitrogen can further enhance the strengthening effect of vanadium on steel. Therefore, some standards also indicate that "if there are enough elements that combine with nitrogen, the nitrogen content can be higher than the standard requirements".