往复式喷射沉积管坯制备中喷射高度的闭环控制

Closed loop control of spray height in tubular preparation with reciprocating spray deposition process

分析了往复式喷射沉积制备大壁厚管坯的工艺原理,研究了喷嘴喷射高度在线检测及闭环控制方法及技术。喷射高度控制系统包括漏包提升执行机构、沉积层厚度在线测量、基于PLC的喷嘴高度控制。提升执行机构采用伺服电机驱动的丝杠螺母机构,针对沉积层间断增长的特点,采用间断提升控制方式;研究了沉积层厚度在线测量方法,分析了收集基底形状误差对测量及控制精度的影响并提出多点测量方案。理论分析表明,采用三点测量法可消减基底形状误差的影响。对不同内径及壁厚的管坯进行了喷射实验,喷射高度累积误差低于5%,较好地满足了大壁厚管坯制备对稳定的喷射高度的要求。

The process principle of reciprocating spray deposition for large thick-wall tubular was analyzed. A new accurate technology of online measurement and closed-loop control for spray height of the nozzle was studied. The control system of spray height consists of executive mechanism of tundish lift, online measurement of deposit layer thickness and control of nozzle height based on PLC. A set of lead-screw mechanism driven by servomotor was applied in the executive mechanism. Aiming at the characteristic of deposit layer growth, the tundish was lifted discontinuously. The measurement method of deposit layer thickness was studied. The influences of shape errors of mandrel on measurement and control accuracy were analyzed and a multi-points measurement technology was presented. Theoretical analysis indicates that the three-point measure along one circle is essential to clear up the influences of the shape errors. Several spray experimentations of the tubular with different inner diameter and wall thickness were carried out. The results indicate that the accumulative error of spray height is less than 5%. This measurement and control technology can well satisfy the need on steady spray height in preparation of large thick-wall tubular.