Analysis of Reasons for Unqualified Reinforcement Quality Project

　　重量偏差是指钢筋实际重量与理论重量的允许偏差，部分中、小型企业不按标准规定组织生产，超负偏差轧制，严重影响了抽样合格率。同时，重量偏差不合格也可能会导致尺寸及工艺、力学性能不合格。表10-5是近几年对热轧带肋钢筋的抽查不合格统计结果，由此看出抽查重量偏差是主要的不合格项。重量偏差超出标准值低的为-14.30%，高的高达-180%，多数超出标准值-20%-40%的范围。

　　Weight deviation refers to the allowable deviation between the actual weight of steel bar and the theoretical weight. Some small and medium-sized enterprises do not organize production according to the standard and roll with excessive negative deviation, which seriously affects the sampling qualified rate. At the same time, unqualified weight deviation may also lead to unqualified size, process and mechanical properties. Table 10-5 is the statistical results of unqualified national spot checks of hot-rolled ribbed steel bars in recent years, which shows that the weight deviation of spot checks is the main unqualified item. The lowest deviation of weight exceeded the standard value was - 14.30%, the highest was - 180%, most exceeded the range of - 20% to - 40%.

　　造成这种现象的原因主要是：

　　The main reasons for this phenomenon are:

　　(l)市场竞争激烈，企业为了降低生产成本，采取不正当的手段来提益，在管理上按重量偏差下限组织生产，造成重量偏差成为主要的不合格项；

　　(l) Competition in the market is fierce. In order to reduce production costs, enterprises adopt improper means to improve efficiency and organize production according to the lower limit of weight deviation in management, resulting in weight deviation as the main unqualified item;

　　(2)企业为迎合中间商的要求，追求利润大化，刻意生产负偏差和超负偏差产品；

　　(2) In order to meet the requirements of middlemen, enterprises pursue profit maximization and deliberately produce negative deviation and ultra-negative deviation products.

　　(3)重量偏差项目未列入建筑工地抽检项目中，是超负偏差产品能存在的原因之一。

　　(3) Weight deviation items are not included in the sampling inspection items of construction sites, which is one of the reasons for the existence of super negative deviation products.

　　历次监督抽查十分重视重量偏差，数据显示，近年来，重量偏差不合格的数量逐年下降，2011年抽查结果未出现重量偏差不合格项，说明了近年来将重量偏差作为检查项目取得了较好的成果。

　　Previous national supervision spot checks attach great importance to weight deviation. Data show that in recent years, the number of unqualified weight deviation declines year by year. In 2011, no unqualified items of weight deviation appeared in the results of spot checks, which shows that good results have been achieved in recent years by taking weight deviation as a key inspection item.

　　尺寸及外形不合格主要表现为肋间距、横肋高及内径，钢筋的外形影响钢筋与混凝土的黏结力。造成此现象的主要原因为：生产企业为了节约成本，普遍按内径负偏差组织生产，易造成内径、横肋高偏小，肋间距偏大的情况。另一方面，部分企业的产品质量管理意识较低，未能使用符合标准的轧辊及严格执行换辊换槽制度。

　　The unqualified dimensions and shapes are mainly rib spacing, transverse rib height and inner diameter. The shape of steel bar affects the bond strength between steel bar and concrete. The main reason for this phenomenon is that in order to save costs, production enterprises generally organize production according to negative deviation of inner diameter, which easily results in smaller inner diameter and transverse rib height and larger rib spacing. On the other hand, some enterprises have low awareness of product quality management, fail to use standard rolls and strictly implement the roll change slot system.

　　化学成分主要表现为C.P.S含量超标。钢中含c量增加，塑性和冲击性降低，钢材的焊接性能变差，冷脆性和时效敏感性增大，耐大气锈蚀性下降；含P愈高，冷脆性愈大，冷脆使钢材的冷加工及焊接性变坏；S含量愈高，热脆现象愈严重，降低钢材的各种力学性能，也使钢材的可焊性、冲击韧性、耐疲劳性和抗腐蚀性等均降低。钢中含C量增加有助于屈服点和抗拉强度的升高，有些企业为了保证屈服点和抗拉强度，C含量就容易超标。另外，P、S含量超标主要是在炼钢过程中控制得不严或没有严格执行钢坯验收制度造成的。

　　The main chemical constituents are C.P.S content exceeding the standard. The higher the content of C in steel, the lower the plasticity and impact, the worse the weldability of steel, the greater the cold brittleness and aging sensitivity, and the lower the atmospheric corrosion resistance; the higher the content of P, the greater the cold brittleness, the worse the cold working and weldability of steel; the higher the content of S, the more serious the hot brittleness, and the lower the various mechanical properties of steel. It also reduces the weldability, impact toughness, fatigue resistance and corrosion resistance of steel. Increasing C content in steel helps to increase yield point and tensile strength. In order to ensure yield point and tensile strength, some enterprises tend to exceed the standard C content. In addition, the content of P and S exceeded the standard mainly due to improper control in steelmaking process or lack of strict implementation of billet acceptance system.

　　力学性能主要为屈服强度不合格，除化学成分、尺寸、重量偏差会对力学及工艺性能造成影n向之外，炼钢、连铸及轧制过程控制不当也是力学性能不合格的原因之一。

　　The main mechanical properties are unqualified yield strength. In addition to the influence of chemical composition, size and weight deviation on mechanical and technological properties, improper control of steelmaking, continuous casting and rolling process is also one of the reasons for unqualified mechanical properties.

　　表面标志不合格项，主要是由于产品标准修订，企业管理没有及时跟进。

　　The unqualified items of surface marks are mainly due to the revision of product standards and the failure of enterprise management to follow up in time.