Welding process control system comprising; • a torch • a current-voltage sensor, a wire feeding unit and speed sensor, a gas tank and gas flow rate sensor, and a cable connected to torch, the system being further characterised by the following features: • fiber bragg grating based optical sensors, said fiber bragg grating based optical sensors comprising at least three core optical fibers produced by fiber Bragg grating method to measure three dimensional elongation levels, the at least three fibers being mounted on the torch and directly on the cable, • shape detecting sensor system adapted to detect the spatial position of the torch by shape detection, the sensor system comprising a light source for providing a wide spectrum light having different wavelengths to be projected on the fibers of the optical sensors and a shape detection sensing device measuring the reflected wavelengths and mathematically finding the extend of the change in the reflectivity indices of the optical fibers so that the elongation of the fibers and the position of the welding torch with respect to a reference position of the shape where the fibers are connected can be measured and determined instantaneously. computer used for collection, evaluation and real-time feed-back of weld parameters and torch position data, wherein the computer is adapted to detect weld quality instantaneously on each weld point by recording time-based position of the torch together with the current, voltage, gas flow rate and wire speed and to continuously monitor the weld quality depending on the time-based position of the torch with respect to the work piece through the fiber bragg grating sensors that are mounted on the weld torch which directly affects the weld quality. • a torch • a current-voltage sensor, a wire feeding unit and speed sensor, a gas tank and gas flow rate sensor, and a cable connected to torch, the system being further characterised by the following features: • fiber bragg grating based optical sensors, said fiber bragg grating based optical sensors comprising at least three core optical fibers produced by fiber Bragg grating method to measure three dimensional elongation levels, the at least three fibers being mounted on the torch and directly on the cable, • shape detecting sensor system adapted to detect the spatial position of the torch by shape detection, the sensor system comprising a light source for providing a wide spectrum light having different wavelengths to be projected on the fibers of the optical sensors and a shape detection sensing device measuring the reflected wavelengths and mathematically finding the extend of the change in the reflectivity indices of the optical fibers so that the elongation of the fibers and the position of the welding torch with respect to a reference position of the shape where the fibers are connected can be measured and determined instantaneously. computer used for collection, evaluation and real-time feed-back of weld parameters and torch position data, wherein the computer is adapted to detect weld quality instantaneously on each weld point by recording time-based position of the torch together with the current, voltage, gas flow rate and wire speed and to continuously monitor the weld quality depending on the time-based position of the torch with respect to the work piece through the fiber bragg grating sensors that are mounted on the weld torch which directly affects the weld quality. • fiber bragg grating based optical sensors, said fiber bragg grating based optical sensors comprising at least three core optical fibers produced by fiber Bragg grating method to measure three dimensional elongation levels, the at least three fibers being mounted on the torch and directly on the cable, • shape detecting sensor system adapted to detect the spatial position of the torch by shape detection, the sensor system comprising a light source for providing a wide spectrum light having different wavelengths to be projected on the fibers of the optical sensors and a shape detection sensing device measuring the reflected wavelengths and mathematically finding the extend of the change in the reflectivity indices of the optical fibers so that the elongation of the fibers and the position of the welding torch with respect to a reference position of the shape where the fibers are connected can be measured and determined instantaneously. computer used for collection, evaluation and real-time feed-back of weld parameters and torch position data, wherein the computer is adapted to detect weld quality instantaneously on each weld point by recording time-based position of the torch together with the current, voltage, gas flow rate and wire speed and to continuously monitor the weld quality depending on the time-based position of the torch with respect to the work piece through the fiber bragg grating sensors that are mounted on the weld torch which directly affects the weld quality.